Merge same db calls for some quota methods

self.db.quota_get_all_by_project is called twice in method limit_check()
and reserve(),
self.db.quota_get_all_by_project_and_user is called twice in method
get_settable_quotas()

Change-Id: Ibe41f49afe16c220ca663a7ad13b61acc08c7775
Closes-bug: 1277068
Merge "Merge same db calls for some quota methods"