qemu-guest-agent should support systemd in addition to pmutils

Hello,

Shouldn't the qemu-guest-agent also support systemd function in addition to the existing call to pm-suspend, shutdown, hwclock.

It's not safe for VM.

This should now be fixed:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=067927d62e097a8a3624a9