remove support for multi-reader dispatch queue

* Under the new postgres backed notify/listen message queue, this never
actually worked. Without using the database to store state, we can not
provide a at-most-once delivery mechanism w/ multi-readers.
* With this change, work is done ONLY on the node that requested for the
work to be done. Under rabbitmq, the node that was first to get the
message off the queue would do the work; presumably the least busy node.

awx/settings/defaults.py

@@ -423,7 +423,6 @@ BROKER_DURABILITY = True
 BROKER_POOL_LIMIT = None
 BROKER_URL = 'redis://localhost:6379'
 BROKER_TRANSPORT_OPTIONS = {}
-CELERY_DEFAULT_QUEUE = 'awx_private_queue'
 CELERYBEAT_SCHEDULE = {
     'tower_scheduler': {
         'task': 'awx.main.tasks.awx_periodic_scheduler',
@@ -452,14 +451,6 @@ CELERYBEAT_SCHEDULE = {
     # 'isolated_heartbeat': set up at the end of production.py and development.py
 }
 
-AWX_CELERY_QUEUES_STATIC = [
-    CELERY_DEFAULT_QUEUE,
-]
-
-AWX_CELERY_BCAST_QUEUES_STATIC = [
-    'tower_broadcast_all',
-]
-
 ASGI_AMQP = {
     'INIT_FUNC': 'awx.prepare_env',
     'MODEL': 'awx.main.models.channels.ChannelGroup',