Ensure routing key is specified in the address for a direct producer

This change is already merged in oslo-incubator.  Original commit
message body includes:

    Porting this fix from oslo.messaging.  This fixes the impl_qpid.py
    driver to allow it to work with the latest stable upstream QPID broker
    (version 0.28).  See the Apache Qpid Jira bug
    https://issues.apache.org/jira/browse/QPID-5557

Change-Id: If71f78e50f8a9b3acfd1e9d02c8271f17c4ebee7
Related-Bug: #1300318
(cherry picked from commit 3597ffca77133101943114b80fd4263bada87f4f)