This commit introduces oslo.messaging service variables in place of
the rabbitmq server. This will enable the use of separate and alternative
messaging system backends for RPC and Notify communications with
minimal impact to the overall deployment configuration.
This patch:
* update service passwords
* add oslo-messaging to group vars
* update inventory group vars for each service
* add common task for oslo messaging vhost/user install
* update service install playbooks
Change-Id: I235bd33a52df5451a62d2c8700a65a1bc093e4d6
929aaf1482