Migrate from oslo-rpc to oslo.messaging

Manila uses oslo-incubator/rpc as an RPC library. During Havana, oslo/rpc was cleaned up and moved into oslo.messaging with a more stable and well-defined API.

oslo-incubator/rpc considered as deprecated now.

Projects are starting to migrate from the old RPC code to the new one in order to keep consistency throughout OpenStack.

This blueprint tracks the work to port Manila to oslo.messaging.
The only user visible change should be that oslo.messaging is a new dependency.

wiki: https://wiki.openstack.org/wiki/Oslo/Messaging
docs: http://docs.openstack.org/developer/oslo.messaging/
git: https://github.com/openstack/oslo.messaging
pypi: https://pypi.python.org/pypi/oslo.messaging