darcs-to-git: Remove propagatedBuildInputs.

I missed this while checking the commit diffs before my last push. And it really
doesn't make sense to propagate ruby all the way up to whatever in the universe
may depend on this package.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/applications/version-management/git-and-tools/darcs-to-git/default.nix

@@ -23,8 +23,6 @@ stdenv.mkDerivation rec {
       darcs-to-git
   '';
 
-  propagatedBuildInputs = [ ruby ];
-
   installPhase = ''
     install -vD darcs-to-git "$out/bin/darcs-to-git"
   '';