Commit 687caeb renamed services.virtualboxHost to programs.virtualbox,
but according to the discussion on the commit, it's probably a better to
put it into virtualisation.virtualbox instead.
The discussion can be found here:
https://github.com/NixOS/nixpkgs/commit/687caeb#commitcomment-12664978
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
6440e9bbfd