Fix python scripts in src/media

media/tools/layout_tests/test_expectations_history_unittest.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.
 
 from datetime import datetime
 from datetime import timedelta
 import time
 import unittest
 
 
@@ skipping 50 matching lines @@
     ctime = time.mktime(ctime.timetuple())
     testname = 'media/video-zoom-controls.html'
     testname_list = [testname]
     result_list = TestExpectationsHistory.GetDiffBetweenTimes(
         ptime, ctime, testname_list)
     self.assertTrue(self.AssertTestName(result_list, testname))
 
 
 if __name__ == '__main__':
   unittest.main()