Comment 15 for bug 1708976

Reviewed: https://review.openstack.org/491351
Committed: https://git.openstack.org/cgit/openstack/puppet-manila/commit/?id=a2ec2cbf0b4d3ed63810ca68c0e0a9a4ebd175a4
Submitter: Jenkins
Branch: master

commit a2ec2cbf0b4d3ed63810ca68c0e0a9a4ebd175a4
Author: ZhongShengping <chdzsp@163.com>
Date: Mon Aug 7 14:06:05 2017 +0800

    Deprecate oslo.messaging rpc_backend option parameter

    Oslo.messaging uses the transport_url to represent the rpc and
    notification messaging driver to use and its full configuration. The
    rpc_backend configuration option is deprecated for removal and
    should not gate oslo.messaging driver configuration options.

    This patch:
    * deprecate rpc_backend
    * remove conditional check
    * update spec tests
    * add release note

    Change-Id: Ia8f531ebb4a33ae1a5f73e212d06be1e41a6ead5
    Closes-Bug: #1708976