Simulate Acquia more closely with php-cgi

Acquia uses php-cgi, not mod_php:
http://www.quora.com/Drupal-CMS/GetPantheon-vs-Omega8-vs-Acquia-pros-and-cons-of-each/answer/Barry-Jaspan/comment/1589243

We should have a role that uses apache2's `mod_fcgid` recipe rather than mod_php.