Override rpc_backend_add_vhost for AMQP 1.0 support
Override rpc_backend_add_vhost for AMQP 1.0 support

Change-Id: Ibb2003bba1371ccd8144f7a03d82fcf78f8b7065
Closes-bug: #1707298
Partial-bug: #1706987

openstack/devstack-plugin-amqp1