Use new synchronization helpers to avoid races when deploying with HA

There are a number of possible races when deploying glance for the
first time:

 - when creating of the database / database user
 - when registering the endpoint and creating users in keystone
Simplify "glance-manage db_sync" call

It's unclear why we had two resources for that, as this is really not
needed.

Also, do not run this for SUSE, where the init script takes care of
this.
Also use crowbar_pacemaker_sync_mark to protect db_sync call
Use crowbar_pacemaker_sync_mark to protect upload of images
Merge pull request #200 from vuntz/sync-marks

Use new synchronization helpers to avoid races when deploying with HA