cabal-install-1.20.0.4: patch the build manually instead of relying on jailbreak

jailbreak-cabal has trouble with that cabal file when built with older versions
of the Cabal library.

pkgs/tools/package-management/cabal-install/1.20.0.4.nix

@@ -18,12 +18,14 @@ cabal.mkDerivation (self: {
     Cabal filepath HTTP HUnit mtl network QuickCheck stm testFramework
     testFrameworkHunit testFrameworkQuickcheck2 time zlib
   ];
-  jailbreak = true;
   doCheck = false;
   postInstall = ''
     mkdir $out/etc
     mv bash-completion $out/etc/bash_completion.d
   '';
+  patchPhase = ''
+    sed -i -e 's|random .*< 1.1,|random,|' cabal-install.cabal
+  '';
   meta = {
     homepage = "http://www.haskell.org/cabal/";
     description = "The command-line interface for Cabal and Hackage";