QPID-5211 - Broker logs spurious "No valid transition from state CLOSED to state CLOSING" on shutdown.

Merged from trunk with the following commands:

svn merge -c 1555690 https://svn.apache.org/repos/asf/qpid/trunk/qpid
svn merge -c 1555695 https://svn.apache.org/repos/asf/qpid/trunk/qpid



git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/0.26@1556287 13f79535-47bb-0310-9956-ffa450edef68