**/*.py: use /usr/bin/env to find python

site_scons/site_tools/environment_tools.py

-#!/usr/bin/python2.4
+#!/usr/bin/env python
 # Copyright 2009, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 236 matching lines @@
 def generate(env):
   # NOTE: SCons requires the use of this name, which fails gpylint.
   """SCons entry point for this tool."""
 
   # Add methods to environment
   env.AddMethod(ApplySConscript)
   env.AddMethod(BuildSConscript)
   env.AddMethod(FilterOut)
   env.AddMethod(RelativePath)
   env.AddMethod(SubstList2)