var refactoring for deployment usecase
nginx config for forum
missing var.
fixing ports.
fixing var inclusion.
cut and paste leave behind.
Be able to override the default secure vars file.

Also always pass in the common.yml vars to plays.
Add common as a dependency of splunk and datadog roles.
Updating port.
Use a var instead of using the number directly.
Accept a mongo uri instead of a host,port and password.
Add an explaination for the count logic.
Merge pull request #642 from edx/feanil/abbey_common

Feanil/abbey common
Add switch on mongo_uri instead of mongo_host.
Removing vestigial fabric files
Merge pull request #644 from edx/jbau/clean-out-fabric

Removing vestigial fabric files
Building the mongo url dynamically.
Merge pull request #643 from edx/e0d/forum-updates

E0d/forum updates
Change how we get the s3 url for the template.
Merge pull request #647 from edx/feanil/unversioned_url

Change how we get the s3 url for the template.