Fixing a nix import path I commited without enough care.

svn path=/nixpkgs/trunk/; revision=14010

pkgs/top-level/all-packages.nix

@@ -3879,7 +3879,7 @@ let
     inherit postgresql mysql sqlite;
   });
 
-  vtk = import /root/nix/vtk/default.nix {
+  vtk = import ../development/libraries/vtk {
     inherit stdenv fetchurl cmake mesa;
     inherit (xlibs) libX11 xproto libXt;
   };