Updated list of Jenkins plugins to install

Removed unused config-backup.yml playbook

Added correct rbenv configuration

Updated plugin list
Removed ssh key for Jenkins

Added JSCover dependency

Changed build directory to /opt/jenkins
Security updates; added xml_grep requirements
Install Mongo ourselves instead of relying on edxlocal role
Fixed incorrect file name to ruby_env
Moved data to /mnt/ for more disk space; added to .bashrc to ensure env
variables set correctly
Reverted changes writing to /mnt/ since it isn't persisted
Configure Mongo to use /mnt so we don't run out of disk space
Install Python packages to the system
Use upstart script to create Jenkins workspace on /mnt
Global virtualenv configuration
Removed dependency on common
Simplified env variable setting
Removed dependency on rbenv and common roles
Fixed permission issue with python .egg cache
Updated python egg cache permissions
Removed .bash_profile and .bashrc config
initial working add of nginx proxy.
reverting accidential commits.
updating handler.
Merge pull request #266 from edx/e0d/add-nginix

E0d/add nginix
Tweaks for jenkins reverse proxy will SSL.
Merge pull request #269 from edx/e0d/nginx-tweaks

E0d/nginx tweaks
Removed Build Flow plugin; added Build Pipeline (and dependencies)