Add conditionals for DD, splunk and new relic.
Merge pull request #963 from edx/feanil/update_ja_playbook

Add conditionals for DD, splunk and new relic.
Add xqueue_consumer service to the xqueue by default.
Merge pull request #964 from edx/feanil/xq_consumer_service

Add xqueue_consumer service to the xqueue by default.
Merge branch 'han/devstack-devpi' of https://github.com/edx/configuration into han/devstack-devpi
setting supervisor role for devpi