haskell-hruby: add missing system dependency and disable broken test suite

Work around https://github.com/bartavelle/hruby/issues/10 and
https://github.com/bartavelle/hruby/issues/9 as suggested in
https://github.com/NixOS/nixpkgs/pull/7442.

pkgs/development/haskell-modules/configuration-common.nix

@@ -22,6 +22,10 @@ self: super: {
   statistics = dontCheck super.statistics;
   text = dontCheck super.text;
 
+  # https://github.com/bartavelle/hruby/issues/10
+  # https://github.com/bartavelle/hruby/issues/9
+  hruby = addExtraLibrary (dontCheck super.hruby) pkgs.ruby_2_1;
+
   # Doesn't compile with lua 5.2.
   hslua = super.hslua.override { lua = pkgs.lua5_1; };