haskell-QuickCheck: drop obsolete override for ghc-8.0.x

Changed files
-3
pkgs
development
haskell-modules
-3
pkgs/development/haskell-modules/configuration-ghc-8.0.x.nix
···
# jailbreak-cabal can use the native Cabal library.
jailbreak-cabal = super.jailbreak-cabal.override { Cabal = null; };
-
# Older versions of QuickCheck don't support our version of Template Haskell.
-
QuickCheck = self.QuickCheck_2_8_2;
-
# https://github.com/hspec/HUnit/issues/7
HUnit = dontCheck super.HUnit;