Don't install php5-fpm

When asked to install php5 before installing libapache-mod-php5 apt
had to guess which SAPI should be installed.  Explicitly declare
this dependency so apt doesn't have to guess.

Bug: 62549
Change-Id: Ica7dab49d5fd3904a8485e3367904b63dd660fca
Merge "Don't install php5-fpm"