isocodes: fix cross to non-Python platforms

These were being patched for the host system's Python, which was
incorrect, as they are not installed.  But the patching turns out not
to be required at all any more, as the build system runs the scripts
with the python3 command instead of directly.

pkgs/development/libraries/iso-codes/default.nix

@@ -9,13 +9,6 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-QI95nfQTVGj6fKNetrBcQAS+pEPYHKWLibLkgkAagrs=";
   };
 
-  patchPhase = ''
-    for i in `find . -name \*.py`
-    do
-        sed -i -e "s|#!/usr/bin/env python|#!${python3}/bin/python|" $i
-    done
-  '';
-
   nativeBuildInputs = [ gettext python3 ];
 
   meta = with lib; {