virHashRemoveAll  remove all  jobs in priv->blockjobs but not set disk->priv->blockjob  is null for qemuDomainObjPrivateDataClear and qemuProcessStop
Description of problem:
it call virHashRemoveAll to remove all jobs in priv->blockjobs but the disk privateData blockjob is not null for qemuDomainObjPrivateDataClear and qemuProcessStop. when virHashRemoveAll is caled, accessing priv->blockjob cause segfault in others.
Steps to reproduce:
1. virsh blockcopy testvm vda /root/disk/centos7-copy.qcow2  --wait --verbose --pivot 
 migrate disk of vm 
2.  poweoff in guest vm
3. libvirt core dump
Additional information:
--Type <RET> for more, q to quit, c to continue without paging--
	Program terminated with signal SIGSEGV, Segmentation fault.
	#0  qemuBlockJobUnregister (vm=0x7f823c045050, job=0x7f827c03ca90) at ../src/qemu/qemu_blockjob.c:211
	211             if (job == diskPriv->blockjob) {
	[Current thread is 1 (Thread 0x7f8283640640 (LWP 152))]
	(gdb) bt
	#0  qemuBlockJobUnregister (vm=0x7f823c045050, job=0x7f827c03ca90) at ../src/qemu/qemu_blockjob.c:211
	#1  qemuBlockJobEventProcessConcluded (asyncJob=VIR_ASYNC_JOB_MIGRATION_OUT, vm=<optimized out>, driver=<optimized out>,
		job=0x7f827c03ca90) at ../src/qemu/qemu_blockjob.c:1678
	#2  qemuBlockJobEventProcess (asyncJob=VIR_ASYNC_JOB_MIGRATION_OUT, job=0x7f827c03ca90, vm=<optimized out>,
		driver=<optimized out>) at ../src/qemu/qemu_blockjob.c:1703
	#3  qemuBlockJobUpdate (vm=<optimized out>, job=0x7f827c03ca90, asyncJob=1) at ../src/qemu/qemu_blockjob.c:1756
	#4  0x00007f828050c95f in qemuMigrationSrcNBDStorageCopyReady (vm=0x7f823c045050, asyncJob=VIR_ASYNC_JOB_MIGRATION_OUT)
		at ../src/qemu/qemu_migration.c:605
	#5  0x00007f8280518ca5 in qemuMigrationSrcNBDStorageCopy (flags=587, nbdURI=<optimized out>, tlsHostname=0x7f823c2b51d0 "",
		tlsAlias=<optimized out>, dconn=0x7f823c014790, migrate_disks=0x7f827c006660, nmigrate_disks=2, speed=<optimized out>,
		host=0x7f827c0156a0 "10.253.160.196", mig=0x7f827c027a30, vm=0x7f823c045050, driver=0x7f823c01ac40)
		at ../src/qemu/qemu_migration.c:1202
	#6  qemuMigrationSrcRun (driver=0x7f823c01ac40, vm=0x7f823c045050, persist_xml=<optimized out>, cookiein=<optimized out>,
		cookieinlen=<optimized out>, cookieout=0x7f828363f500, cookieoutlen=0x7f828363f4d4, flags=587, resource=1024,
		spec=0x7f828363f330, dconn=0x7f823c014790, graphicsuri=0x0, nmigrate_disks=2, migrate_disks=0x7f827c006660,
		migParams=0x7f827c00d890, nbdURI=0x0) at ../src/qemu/qemu_migration.c:4167
	#7  0x00007f828051a5dd in qemuMigrationSrcPerformNative (driver=0x7f823c01ac40, vm=0x7f823c045050,
		persist_xml=0x7f827c020660 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		uri=<optimized out>,
		cookiein=0x7f827c0519e0 "<qemu-migration>\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <hostname>ceasphere-node-1</hostname>\n  <hostuuid>5b0a0842-6535-27c1-b2e7-89c4ac4fd785</hostuuid>"...,
		cookieinlen=876, cookieout=0x7f828363f500, cookieoutlen=0x7f828363f4d4, flags=587, resource=1024, dconn=0x7f823c014790,
		graphicsuri=0x0, nmigrate_disks=2, migrate_disks=0x7f827c006660, migParams=0x7f827c00d890, nbdURI=0x0)
		at ../src/qemu/qemu_migration.c:4506
	#8  0x00007f828051c3e3 in qemuMigrationSrcPerformPeer2Peer3 (flags=<optimized out>, useParams=true, bandwidth=<optimized out>,
		migParams=0x7f827c00d890, nbdURI=0x0, nbdPort=0, migrate_disks=0x7f827c006660, nmigrate_disks=<optimized out>,
		listenAddress=<optimized out>, graphicsuri=0x0, uri=<optimized out>, dname=0x0,
		persist_xml=0x7f827c020660 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		xmlin=<optimized out>, vm=0x7f823c045050,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock", dconn=0x7f823c014790, sconn=0x7f826c00e890, driver=0x7f823c01ac40) at ../src/qemu/qemu_migration.c:4925
	#9  qemuMigrationSrcPerformPeer2Peer (v3proto=<synthetic pointer>, resource=<optimized out>, dname=0x0, flags=587,
		migParams=0x7f827c00d890, nbdURI=0x0, nbdPort=0, migrate_disks=0x7f827c006660, nmigrate_disks=<optimized out>,
		listenAddress=<optimized out>, graphicsuri=0x0, uri=<optimized out>,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock",
	--Type <RET> for more, q to quit, c to continue without paging--
		persist_xml=0x7f827c020660 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		xmlin=<optimized out>, vm=0x7f823c045050, sconn=0x7f826c00e890, driver=0x7f823c01ac40) at ../src/qemu/qemu_migration.c:5230
	#10 qemuMigrationSrcPerformJob (driver=0x7f823c01ac40, conn=0x7f826c00e890, vm=0x7f823c045050, xmlin=<optimized out>,
		persist_xml=0x7f827c020660 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock", uri=<optimized out>, graphicsuri=<optimized out>, listenAddress=<optimized out>, nmigrate_disks=<optimized out>,
		migrate_disks=<optimized out>, nbdPort=0, nbdURI=<optimized out>, migParams=<optimized out>, cookiein=<optimized out>,
		cookieinlen=0, cookieout=<optimized out>, cookieoutlen=<optimized out>, flags=<optimized out>, dname=<optimized out>,
		resource=<optimized out>, v3proto=<optimized out>) at ../src/qemu/qemu_migration.c:5307
	#11 0x00007f828051cce7 in qemuMigrationSrcPerform (driver=0x7f823c01ac40, conn=0x7f826c00e890, vm=0x7f823c045050,
		xmlin=0x7f827c01e630 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		persist_xml=0x7f827c020660 "<domain type=\"kvm\">\n  <name>default_vm-8altm</name>\n  <uuid>4a40fa64-fd9b-5078-8574-3ce5d0041d31</uuid>\n  <metadata>\n    <nodeagent xmlns=\"http://kubevirt.io/node-agent.io\">\n      <vmid>13fb0e90-2930-"...,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock", uri=0x556a1f856b20 "tcp://10.253.160.196:27939", graphicsuri=0x0, listenAddress=0x0, nmigrate_disks=2,
		migrate_disks=0x7f827c006660, nbdPort=0, nbdURI=0x0, migParams=0x7f827c00d890, cookiein=0x0, cookieinlen=0,
		cookieout=0x7f828363f8a8, cookieoutlen=0x7f828363f89c, flags=587, dname=0x0, resource=1024, v3proto=true)
		at ../src/qemu/qemu_migration.c:5513
	#12 0x00007f82804e34d0 in qemuDomainMigratePerform3Params (dom=0x7f8268002ee0,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock", params=0x7f827c01e380, nparams=7, cookiein=0x0, cookieinlen=0, cookieout=0x7f828363f8a8,
		cookieoutlen=0x7f828363f89c, flags=587) at ../src/qemu/qemu_driver.c:11796
	#13 0x00007f82853256d6 in virDomainMigratePerform3Params (domain=domain@entry=0x7f8268002ee0,
		dconnuri=0x7f827c00c2b0 "qemu+unix:///system?socket=/var/run/kubevirt/migrationproxy/13fb0e90-2930-4f0b-959a-cc40346e7d64-source.sock", params=<optimized out>, nparams=7, cookiein=0x0, cookieinlen=0, cookieout=0x7f828363f8a8,
		cookieoutlen=0x7f828363f89c, flags=587) at ../src/libvirt-domain.c:5165
	#14 0x0000556a1f200f17 in remoteDispatchDomainMigratePerform3Params (server=<optimized out>, msg=0x556a1f86ba40,
		ret=0x7f827c0197f0, args=0x7f827c019520, rerr=0x7f828363f9a0, client=<optimized out>)
		at ../src/remote/remote_daemon_dispatch.c:5710
	#15 remoteDispatchDomainMigratePerform3ParamsHelper (server=<optimized out>, client=<optimized out>, msg=0x556a1f86ba40,
		rerr=0x7f828363f9a0, args=0x7f827c019520, ret=0x7f827c0197f0) at src/remote/remote_daemon_dispatch_stubs.h:8761
	#16 0x00007f828522c676 in virNetServerProgramDispatchCall (msg=0x556a1f86ba40, client=0x556a1f85b510, server=0x556a1f84c080,
		prog=0x556a1f850410) at ../src/rpc/virnetserverprogram.c:428
	#17 virNetServerProgramDispatch (prog=0x556a1f850410, server=0x556a1f84c080, client=0x556a1f85b510, msg=0x556a1f86ba40)
		at ../src/rpc/virnetserverprogram.c:302
	--Type <RET> for more, q to quit, c to continue without paging--
	#18 0x00007f82852331d8 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>,
		srv=0x556a1f84c080) at ../src/rpc/virnetserver.c:140
	#19 virNetServerHandleJob (jobOpaque=0x556a1f861f90, opaque=0x556a1f84c080) at ../src/rpc/virnetserver.c:160
	#20 0x00007f8285170653 in virThreadPoolWorker (opaque=<optimized out>) at ../src/util/virthreadpool.c:164
	#21 0x00007f828516fc09 in virThreadHelper (data=<optimized out>) at ../src/util/virthread.c:256
	#22 0x00007f8284b10802 in start_thread () from /lib64/libc.so.6
	#23 0x00007f8284ab0450 in clone3 () from /lib64/libc.so.6


	(gdb) p job
	$1 = (qemuBlockJobData *) 0x7f827c03ca90
	(gdb) p *job
	$2 = {parent = {parent_instance = {g_type_instance = {g_class = 0x7f827c00dc90}, ref_count = 1, qdata = 0x0}},
	  name = 0x7f827c038cd0 "drive-ua-vol-vm-8altm", disk = 0x7f823c0475c0, chain = 0x556a1f8548f0, mirrorChain = 0x0,
	  jobflags = 0, jobflagsmissing = false, data = {pull = {base = 0x0}, commit = {topparent = 0x0, top = 0x0, base = 0x0,
		  deleteCommittedImages = false}, create = {storage = false, src = 0x0}, copy = {shallownew = false}, backup = {
		  store = 0x0, bitmap = 0x0}}, type = 2, state = 5, errmsg = 0x0, synchronous = true, newstate = 6, brokentype = 0,
	  invalidData = false, reconnected = false}
	(gdb) p *job->disk
	$3 = {src = 0x7f823c047, privateData = 0xffe8eec3390edb93, device = VIR_DOMAIN_DISK_DEVICE_DISK,
	  bus = VIR_DOMAIN_DISK_BUS_VIRTIO, dst = 0x7f823c047300 "\327_'ą\177", tray_status = VIR_DOMAIN_DISK_TRAY_CLOSED,
	  removable = VIR_TRISTATE_SWITCH_ABSENT, rotation_rate = 0, mirror = 0x0, mirrorState = 0, mirrorJob = 0, geometry = {
		cylinders = 0, heads = 0, sectors = 0, trans = VIR_DOMAIN_DISK_TRANS_DEFAULT}, blockio = {logical_block_size = 0,
		physical_block_size = 0}, blkdeviotune = {total_bytes_sec = 0, read_bytes_sec = 0, write_bytes_sec = 0,
		total_iops_sec = 0, read_iops_sec = 0, write_iops_sec = 0, total_bytes_sec_max = 0, read_bytes_sec_max = 0,
		write_bytes_sec_max = 0, total_iops_sec_max = 0, read_iops_sec_max = 0, write_iops_sec_max = 0, size_iops_sec = 0,
		group_name = 0x0, total_bytes_sec_max_length = 0, read_bytes_sec_max_length = 0, write_bytes_sec_max_length = 0,
		total_iops_sec_max_length = 0, read_iops_sec_max_length = 0, write_iops_sec_max_length = 0},
	  driverName = 0x7f823c047270 "\267\262'ą\177", serial = 0x0, wwn = 0x0, vendor = 0x0, product = 0x0,
	  cachemode = VIR_DOMAIN_DISK_CACHE_DISABLE, error_policy = VIR_DOMAIN_DISK_ERROR_POLICY_RETRY,
	  rerror_policy = VIR_DOMAIN_DISK_ERROR_POLICY_DEFAULT, retry_interval = 1000, retry_timeout = 0,
	  iomode = VIR_DOMAIN_DISK_IO_NATIVE, ioeventfd = VIR_TRISTATE_SWITCH_ABSENT, event_idx = VIR_TRISTATE_SWITCH_ABSENT,
	  copy_on_read = VIR_TRISTATE_SWITCH_ABSENT, snapshot = VIR_DOMAIN_SNAPSHOT_LOCATION_DEFAULT,
	  startupPolicy = VIR_DOMAIN_STARTUP_POLICY_DEFAULT, transient = false, transientShareBacking = VIR_TRISTATE_BOOL_ABSENT,
	  info = {alias = 0x0, type = 0, addr = {pci = {domain = 0, bus = 0, slot = 0, function = 0,
			multi = VIR_TRISTATE_SWITCH_ABSENT, extFlags = 0, zpci = {uid = {value = 0, isSet = false}, fid = {value = 0,
				isSet = false}}}, drive = {controller = 0, bus = 0, target = 0, unit = 0, diskbus = 0}, vioserial = {
			controller = 0, bus = 0, port = 0}, ccid = {controller = 0, slot = 0}, usb = {bus = 0, port = {0, 0, 0, 0}},
		  spaprvio = {reg = 0, has_reg = false}, ccw = {cssid = 0, ssid = 0, devno = 0, assigned = false}, isa = {iobase = 0,
			irq = 0}, dimm = {slot = 0, base = 0}}, mastertype = 0, master = {usb = {startport = 0}},
		romenabled = VIR_TRISTATE_BOOL_ABSENT, rombar = VIR_TRISTATE_SWITCH_ABSENT, romfile = 0x0, bootIndex = 1,
		effectiveBootIndex = 1, acpiIndex = 0, pciConnectFlags = 9, pciAddrExtFlags = 0, loadparm = 0x0, isolationGroup = 0,
		isolationGroupLocked = false}, rawio = VIR_TRISTATE_BOOL_ABSENT, sgio = VIR_DOMAIN_DEVICE_SGIO_DEFAULT,
	  discard = VIR_DOMAIN_DISK_DISCARD_DEFAULT, iothread = 1, detect_zeroes = VIR_DOMAIN_DISK_DETECT_ZEROES_DEFAULT,
	  domain_name = 0x0, queues = 0, queue_size = 0, model = VIR_DOMAIN_DISK_MODEL_DEFAULT, virtio = 0x7f823c047170,
		  diskElementAuth = false, diskElementEnc = false}