spec: Don't save/restore running VMs on libvirt-client update

spec: Don't save/restore running VMs on libvirt-client update

Restarting an active libvirt-guests.service is the equivalent of
doing:

/usr/libexec/libvirt-guests.sh stop
/usr/libexec/libvirt-guests.sh start

Which in a default configuration will managedsave every running VM,
and then restore them. Certainly not something we should do every
time the libvirt-client RPM is updated.

Just drop the try-restart attempt, I don't know what purpose it
serves anyways.

https://bugzilla.redhat.com/show_bug.cgi?id=962225