Devstack and general environment improvements

Make sure your config file is an environment variables.
Remove several hardcoded settings files from the devstack commands.

docker/build/xqueue/ansible_overrides.yml

@@ -2,6 +2,7 @@
 XQUEUE_SYSLOG_SERVER: "localhost"
 XQUEUE_RABBITMQ_HOSTNAME: "edx.devstack.rabbit"
 XQUEUE_MYSQL_HOST: "edx.devstack.mysql"
+XQUEUE_SETTINGS: "devstack"
 xqueue_gunicorn_port: 18040
 xqueue_gunicorn_host: 0.0.0.0
 devstack: true

playbooks/roles/xqueue/defaults/main.yml

@@ -54,7 +54,6 @@ XQUEUE_MYSQL_CONN_MAX_AGE: 0 # This is Django's default https://docs.djangoproje
 
 XQUEUE_NEWRELIC_APPNAME: "{{ COMMON_ENVIRONMENT }}-{{ COMMON_DEPLOYMENT }}-xqueue"
 XQUEUE_CONSUMER_NEWRELIC_APPNAME: "{{ COMMON_ENVIRONMENT }}-{{ COMMON_DEPLOYMENT }}-xqueue_consumer"
-XQUEUE_SETTINGS_MODULE: "xqueue.aws_settings"
 # Set the number of gunicorn front end workers explicitely for xqueue
 XQUEUE_WORKERS: !!null
 
@@ -141,8 +140,9 @@ xqueue_gunicorn_port: 8040
 xqueue_gunicorn_host: 127.0.0.1
 
 xqueue_environment:
-  DJANGO_SETTINGS_MODULE: '{{ XQUEUE_SETTINGS_MODULE }}'
+  DJANGO_SETTINGS_MODULE: 'xqueue.{{ XQUEUE_SETTINGS }}'
   PATH: '{{ xqueue_venv_bin }}:{{ ansible_env.PATH }}'
+  XQUEUE_CFG: '{{ COMMON_CFG_DIR }}/xqueue.yml'
 
 xqueue_requirements_file:      "{{ xqueue_code_dir }}/requirements.txt"
 xqueue_openstack_requirements_file: "{{ xqueue_code_dir }}/openstack-requirements.txt"