rpm: Remove custom libvirtd restart logic

rpm: Remove custom libvirtd restart logic

This logic was necessary when socket activation was introduced
in libvirt 5.6.0/5.7.0 in order to guarantee smooth upgrades.

These days, even the oldest platform that we target ships a
version of libvirtd that implements socket activation, so the
additional code is no longer useful and we can treat libvirtd
the same as all other services.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>