reprepro: stop importing Facebook's HHVM packages

We don't use them; we have our own. This was just for testing.
Reverts the following changes:

I4354eae8d: "reprepro: import Facebook's HHVM pkgs, for Labs / Vagrant usage only"
I0fe5e7b5b: "hhvm: add hhvm-fastcgi too"

Change-Id: Iae0251f80a238d785e5be90165d84bf225d8bd1e