Remove config.ru notification to Nginx::Vhost

The Nginx virtual host should not care about the config.ru file, this
file is only relevant to the Rack compatible server being used, either
Thin or Unicorn. So we subscribe to the config.ru Concat resource in
both the thin::app and unicorn::app resources.
Merge pull request #71 from geoffgarside/config.ru-notify

Remove config.ru notification to Nginx::Vhost