Revert Merge x-updates into master due to mesa bloat

See #490 discussion.

This reverts commit 1278859d31, reversing
changes made to 0c020c98f9.

Conflicts:
	pkgs/desktops/xfce/core/xfce4-session.nix (take master)
	pkgs/lib/misc.nix (auto)

pkgs/development/interpreters/python/2.7/default.nix

@@ -9,11 +9,11 @@ with stdenv.lib;
 let
 
   majorVersion = "2.7";
-  version = "${majorVersion}.4";
+  version = "${majorVersion}.3";
 
   src = fetchurl {
     url = "http://www.python.org/ftp/python/${version}/Python-${version}.tar.bz2";
-    sha256 = "0nd3x4j2w8pi9ac3pawrzb5i3s88hw0aasr08dprdv7q81fp0pq3";
+    sha256 = "0g3672il41rcfjk7sphfqdsa6qf53y8g3ai8yk1sslxi3khmfr3j";
   };
 
   patches =

pkgs/development/interpreters/python/3.3/default.nix

@@ -58,7 +58,7 @@ stdenv.mkDerivation {
     readlineSupport = readline != null;
     opensslSupport = openssl != null;
     tkSupport = (tk != null) && (tcl != null) && (libX11 != null) && (xproto != null);
-    libPrefix = "python${majorVersion}m";
+    libPrefix = "python${majorVersion}";
   };
 
   enableParallelBuilding = true;