QPID-5211: [Java Broker] Prevent spurious 'No valid transition from state CLOSED..' when shutting down a broker configure with a JDBC or BDB vhost

Correct typo, accidentally left AtomicBoolean#getAndSet call in too.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1555695 13f79535-47bb-0310-9956-ffa450edef68