haskell-libmpd: test suite build is broken by recent hspec update

pkgs/development/libraries/haskell/libmpd/default.nix

···
     dataDefault hspec HUnit mtl network QuickCheck text time utf8String
   ];
   jailbreak = true;
+  doCheck = false;
   meta = {
     homepage = "http://github.com/joachifm/libmpd-haskell#readme";
     description = "An MPD client library";