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

Related-Bug: LP #1300318
Resolves: rhbz#1106858