Load mod_actions and mod_fastcgi in hhvm virtualhost def

I am not sure if placing it there adversely impacts performance. It certainly
is awkward. But the Puppet code makes it very difficult to load a module on
just a few hosts in labs. (Example: it ignores conf.d/* completely, and thus
a2enmod has no effect.) So: OK for now.

Change-Id: I87224b47ef5d5e199c858f589319d596f0b9f239