Make prior RabbitMQ TLS changelog more accurate, and add a new entry for setting `XQUEUE_RABBITMQ_TLS` to false

Closes #3717.

update mysqlclientcore for 16.04

Put the password generator into a real .sh file

There were two whens in these tasks

Ansible warned at the top, rather than complaining louder.

add the ec2 plugin + deps

Ansible Script to rollback migrations

turn off mongo auth for platform jenkins

Update Vagrantfiles for ficus.1

(cherry picked from commit bc971b0f)

Source python virtual env in analytics_api_env

https://wiki.jenkins-ci.org/display/JENKINS/Amazon+EC2+Plugin

Enable Mongo auth

Mroytman/update dockerfile

TNL-6278 Adds in xvfb and firefox to tools_jenkins for bok-choy tests

Sleep before attempting to restart forums

Update Vagrantfiles

(cherry picked from commit 8d1a52fe)

If it fails with this exit code, rake search:validate failed, meaning
the elasticsearch mappings or index isn't in sync with the code. To
avoid bouncing the app too quickly when this happens, sleep for a bit

The API changed slightly.

Use the ubuntu keyserver to retrieve the edX PPA key.

Explicitly set the permissions for the supervisor config for celery.