Fix python scripts in src/media

media/tools/constrained_network_server/cns_test.py

-#!/usr/bin/python
-
+#!/usr/bin/env python
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Tests for Constrained Network Server."""
 import os
 import signal
 import subprocess
 import tempfile
 import time
@@ skipping 140 matching lines @@
     # Verify the request took longer than the requested latency.
     self.assertTrue(time.time() - now > self._LATENCY_TEST_SECS)
 
     # Verify the server properly redirected the URL.
     self.assertEquals(f.geturl(), base_url.replace(
         str(cns._DEFAULT_SERVING_PORT), str(cns._DEFAULT_CNS_PORT_RANGE[0])))
 
 
 if __name__ == '__main__':
   unittest.main()