Ensure that qpid connection is closed (from oslo)

This is commit a9bc62814d in oslo-incubator

Fixes bug 1172922

When reestablishing a session and a connection already exists the
existing connection will be closed prior to opening the new one.

Change-Id: I9a25800fe4b56eba89d550e3461ce095bf902f0a
Merge "Ensure that qpid connection is closed (from oslo)"