This introduces oslo.messaging variables that define the RPC and
Notify transports for the OpenStack services. These parameters replace
the rabbitmq values and are used to generate the messaging
transport_url for the service. The association of the messaging
backend server to the oslo.messaging services will then be transparent
to the trove service.
This patch:
* Add oslo.messaging variables for RPC and Notify to defaults
* Update transport_url generation (add for notification)
* Add oslo.messaging to tests inventory
* Update tests
* Update docs
* Update extras
* Add release note
Change-Id: Ia01317343ae6fbc790d64b5ba282c8c069750d45