Update mongo handler for the new version of mongo.
Merge pull request #1646 from edx/feanil/update_mongo_handler

Update mongo handler for the new version of mongo.
Switch from legacy variable templating system to Jinja2 everywhere
Add spacing to match coding conventions.
Add back dollarsigns to the vars that need it.
Remove last known dollar vars.
Upgrade ansible and its dependencies.
Fix spacing to deal with a bug introduced in ansible 1.7.2
Update default for 3rd party auth to an empty dict.
Revert to ansible 1.5.5 due to a template bug.

See https://github.com/ansible/ansible/issues/9362
Put back the $ vars that we need for now.

Among other things, booleans don't get passed around correctly.
Disable old ORA on sandboxes by default.
Add the new version of apt.
Remove the .py from the file.