* Using Kombu's default Broadcast() constructor requires only 1
parameter. That parameter defines the exchange name and the queue name
is randomly generated per-node.
* This caused problems if/when celery enters an infinite restart loop
because too many rabbit queues get created and rabbit OOM's
(gracefully).
* To remedy this we tell Broadcast the queue name to use, which is
derived from some constant + the node name so that the per-node queue
name is stable.