Ensure swift-proxy containers aren't created when not using swift.

* Adjust the environment so that swift_proxy isn't apart of infra
* Remove redundant proxy_container group
* Fix md5sum for environment file in rpc_user_config

HAProxy will work without swift-proxy containers as the group exists
in the inventory but is empty. The VIP will be created but has no
backends.

Fixes: #392
Fixes: #393