Run "glance-manage db_sync" on SUSE when HA is enabled

So far, we were not running it because the init script on SUSE does run
it. But with HA enabled, the service starts at the same time on all
nodes, which may result in failures on some nodes because db_sync can't
be run multiple times simultaneously. The end result is that the
pacemaker resource was possilby failing on some nodes, which then
required some manual cleanup.