Comment # 40 on bug 1020363 from Marius Kittler

I still think starting the user D-Bus daemon via systemd is the right thing to
do.

> It seems that pulseaudio and `spice-vdagent` are preventing the old session to close. When starting also pulseaudio via systemd and killing `spice-vdagent` before isolating the graphical target the issue doesn't occur.

So if my initial observation is still valid we could easily fix this by
starting pulsaudio via systemd. This would at least reduce the problem to
`spice-vdagent`.
I'm not sure about it, but apparently it is just a KVM/qemu guest thing so it
is not really important. In openQA we could workaround the issue just by
quitting it manually before the isolation.