qt5: make qt-5.4.1 default

pkgs/development/libraries/phonon/qt4/default.nix

@@ -1,7 +1,4 @@
-{ stdenv, fetchurl, cmake, automoc4, pulseaudio
-, qt4 ? null, qt5 ? null, withQt5 ? false }:
-
-assert (withQt5 -> qt5 != null); assert (!withQt5 -> qt4 != null);
+{ stdenv, fetchurl, cmake, automoc4, pulseaudio, qt4 }:
 
 with stdenv.lib;
 
@@ -17,12 +14,10 @@ stdenv.mkDerivation rec {
     sha256 = "1l97h1jj3gvl1chx1qbipizfvjgqc05wrhdcflc76c2krlk03jmn";
   };
 
-  buildInputs = [ (if withQt5 then qt5 else qt4) pulseaudio ];
+  buildInputs = [ qt4 pulseaudio ];
 
   nativeBuildInputs = [ cmake automoc4 ];
 
-  cmakeFlags = optional withQt5 "-DPHONON_BUILD_PHONON4QT5=ON";
-
   meta = {
     homepage = http://phonon.kde.org/;
     description = "Multimedia API for Qt";