haskell-vector: mark broken on GHC 7.6.x and earlier

pkgs/development/haskell-modules/configuration-ghc-7.4.x.nix

···
   QuickCheck = addBuildDepends super.QuickCheck (with self; [nats semigroups]);
   optparse-applicative = addBuildDepend super.optparse-applicative self.semigroups;
   text = addBuildDepend super.text self.bytestring-builder;
+  vector = addBuildDepend super.vector self.semigroups;
 
   # Newer versions don't compile any longer.
   network_2_6_3_1 = dontCheck super.network_2_6_3_1;

pkgs/development/haskell-modules/configuration-ghc-7.6.x.nix

···
   QuickCheck = addBuildDepend super.QuickCheck self.semigroups;
   void = addBuildDepends super.void (with self; [hashable semigroups]);
   optparse-applicative = addBuildDepend super.optparse-applicative self.semigroups;
+  vector = addBuildDepend super.vector self.semigroups;
 
   # Need a newer version of Cabal to interpret their build instructions.
   cmdargs = addSetupDepend super.cmdargs self.Cabal_1_24_2_0;