commit: 4fe6d78 "virtio: postpone the execution of event_notifier_cleanup function" will cause vhost-user device crash

The new commit: 4fe6d78 break the existing vhost-user devices, such as vhost-user-scsi/blk and vhost-vsocks when exit the host driver,  kvm_io_ioeventfd_del will hit the abort().

Thanks for the bug report. Patch has now been reverted:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=1ef8185a0613dd2ed2