due to https://github.com/edx/edx-platform/blob/master/common/lib/xmodule/xmodule/open_ended_grading_classes/openendedchild.py#L79

I added  open-ended-message to XQUEUE_QUEUES

Instead of enabling basic auth per role this makes it
an nginx parameter which makes more sense for sandboxes
and probably other servers where we want basic auth turned on

`XQUEUE_BASIC_AUTH` was declared twice for two different usages: activating/deactivating
the auth (boolean), and a [login, password] list. Split the second usage (login/password
list) into two separate variables, like the corresponding django_auth variables.

prefix

Too much logs in DEBUG..

Was causing a flood of error logs in /mnt/logs/edx.log

Oct 11 15:48:21 hostname [queue.management.commands.run_consumer][env:sandbox] INFO [hostname  1630] [run_consumer.py:69] -  [*] Starting queue consumers...
Oct 11 15:48:21 hostname [pika.callback][env:sandbox] DEBUG [hostname  1630] [callback.py:161] - Added: {'callback': <bound method Worker.on_connected of Worker (u'http://localhost:18050', u'edX-DemoX')>, 'only': None, 'one_shot': False, 'arguments': None}
Oct 11 15:48:21 hostname [pika.callback][env:sandbox] DEBUG [hostname  1630] [callback.py:161] - Added: {'callback': <bound method SelectConnection._on_connection_start of <pika.adapters.select_connection.SelectConnection object at 0x2383990>>, 'only': None, 'one_shot': True, 'arguments': None, 'calls': 1}
Oct 11 15:48:21 hostname [pika.connection][env:sandbox] DEBUG [hostname  1630] [connection.py:810] - Attempting connection
Oct 11 15:48:21 hostname [pika.adapters.base_connection][env:sandbox] DEBUG [hostname  1630] [base_connection.py:98] - Connecting the adapter to the remote host
Oct 11 15:48:21 hostname [pika.adapters.base_connection][env:sandbox] DEBUG [hostname  1630] [base_connection.py:153] - Creating the socket
Oct 11 15:48:21 hostname [pika.adapters.base_connection][env:sandbox] INFO [hostname  1630] [base_connection.py:163] - Connecting fd 5 to $XQUEUE_RABBIT_HOSTNAME:5672
Oct 11 15:48:21 hostname [pika.adapters.base_connection][env:sandbox] ERROR [hostname  1630] [base_connection.py:109] - socket error: Temporary failure in name resolution
Oct 11 15:48:21 hostname [pika.adapters.base_connection][env:sandbox] ERROR [hostname  1630] [base_connection.py:118] - Could not connect: Temporary failure in name resolution