Gracefully handle qpid errors

If a qpid error occurs when Glance is sending notifications, the
qpid connection may not be cleaned up properly.  This change catches
qpid exceptions to allow proper error handling.

Fixes bug 1164681

Change-Id: Ica3ef54b958e4efe3932b90d721324e7860b1ea4
Merge "Gracefully handle qpid errors"