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

build/download_utils.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.
 
 """A library to assist automatically downloading files.
 
 This library is used by scripts that download tarballs, zipfiles, etc. as part
 of the build process.
 """
 
@@ skipping 298 matching lines @@
   EnsureFileCanBeWritten(filename)
   http_download.HttpDownload(url, filename)
 
   if hash_val:
     tar_hash = HashFile(filename)
     if hash_val != tar_hash:
       raise HashError(actual_hash=tar_hash, expected_hash=hash_val,
                       download_url=url)
 
   return True