[ClusterLabs] corosync.service (and sbd.service) are not stopper on pacemaker shutdown when corosync-qdevice is used

[Andrei Borzenkov]

corosync.service sets StopWhenUnneded=yes which normally stops it when
pacemaker is shut down. Unfortunately, corosync-qdevice.service declares
Requires=corosync.service and corosync-qdevice.service itself is *not*
stopped when pacemaker.service is stopped. Which means corosync.service
remains "needed" and is never stopped.

Also sbd.service (which is PartOf=corosync.service) remains running as well.

The latter is really bad, as it means sbd watchdog can kick in at any
time when user believes cluster stack is safely stopped. In particular
if qnetd is not accessible (think network reconfiguration).