Revert "don't propagate recursivePthLoader, it is needed to process it already"

This reverts commit edd160452e.

If we propagate it, derivations that use a python package will also
get the recursivePthLoader needed to process the pth files of the
package.

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

@@ -53,6 +53,9 @@ python.stdenv.mkDerivation (attrs // {
 
   buildInputs = [ python wrapPython setuptools ] ++ buildInputs ++ pythonPath;
 
+  # recursivePthLoader is responsible for loading pth files
+  propagatedBuildInputs = propagatedBuildInputs ++ [ recursivePthLoader ];
+
   buildInputStrings = map toString buildInputs;
 
   pythonPath = [ setuptools ] ++ pythonPath;