QPID-4780: Bug 889552 - HA broker deadlock after loss of primary broker.

Lock ordering deadlock found by inspection of code and stack trace:

- thread 1: Link::ioThreadProcessing(Link:lock)-> QueueReplicator::initializeBridge(QueueReplicator::lock)
- thread 2: QueueReplicator::destroy(QueueReplicator::lock)-> Bridge::destroy(Link::lock)

This patch breaks the lock by removing locking around Bridge::destroy in QueueReplicator::destroy.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1476305 13f79535-47bb-0310-9956-ffa450edef68