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.
This patch:
* Add oslo.messaging variables for RPC and Notify to defaults
* Update transport_url generation in conf
* Add oslo.messaging to tests inventory and update tests
* Install extra packages for optional drivers
* Add release note
Change-Id: I0612252927f81b3584054f6cd77a2826c5d3fc3b
cfddca21eb