This patch refactors the database creation to db_setup.yml which
will eventually be managed by openstack-ansible-tests.
This also re-orders the mq_setup to be done earlier so these system
level dependencies are ready before service activation.
We have been using run_once only for keystone role. As we have a
keystone group in the inventory, we re replacing run_once for the
conditionals to match the pattern across all the other roles.
Change-Id: Idb5ea861a87fe077f7c716f1157acd8e39257c5b
4ea410ffcd