KeyAffinityService race condition on view change

KeyAffinityService#getKeyForAddress runs in a tight loop looking for keys:

    queue = address2key.get(address)
    while (result == null)
        result = queue.poll()

KeyAffinityService#handleViewChange clears and resets the queue list on membership change:

    address2key.clear()
    for each address
        map.put(address, new queue)

If a view change comes in after getKeyForAddress gets the queue, and the queue is empty, it will get stuck in a tight loop looking at the wrong queue forever while new keys are added to the new queue.