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

build/working_directory.py

-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Classes to create working directories of various sorts."""
 
 import logging
 import os
 import shutil
 import tempfile
@@ skipping 41 matching lines @@
   Example uses:
     for TemporaryWorkingDirectory() as work_dir:
       ...do stuff in work_dir...
   """
   def __enter__(self):
     self._work_dir = tempfile.mkdtemp(prefix='workdir', suffix='.tmp')
     return self._work_dir
 
   def __exit__(self, _type, _value, _trackback):
     shutil.rmtree(self._work_dir)