do not create e.g pth file for build inputs

if they are really needed they will be in pth file created by
easy_install. If that does not work, they need to be put into
propagatedBuildInputs or the setup.py fixed.

see #210

pkgs/development/python-modules/generic/default.nix

@@ -91,7 +91,8 @@ python.stdenv.mkDerivation (attrs // {
     ''
       wrapPythonPrograms
 
-      createBuildInputsPth build-inputs "$buildInputStrings"
+      # these should already be in $name.pth
+      #createBuildInputsPth build-inputs "$buildInputStrings"
       for inputsfile in propagated-build-inputs propagated-build-native-inputs; do
         if test -e $out/nix-support/$inputsfile; then
             createBuildInputsPth $inputsfile "$(cat $out/nix-support/$inputsfile)"