Ensure php5-fpm isn't installed

Summary:
PHP modules have a virtual dependency on some kind of PHP implementation.
php5-cli must be installed before any php modules so that some other PHP
implementation (fpm, mod_php, ...) isn't installed instead.

Test Plan:
Added tests. They didn't fail even before I implemented the fix,
because this problem doesn't manifest on saucy, but only precise. However, I'm
confident this solution works because I've tested it in rPPHAB.

Reviewers: #macpros_internal, jbowman

Reviewed By: #macpros_internal, jbowman

Subscribers: jbowman

Differential Revision: http://phabricator.macprofessionals.lan/D19