Remove thirdparty/unittest2 from webkitpy and require python2.7.

Tools/Scripts/webkitpy/test/runner.py

 # Copyright (C) 2012 Google, Inc.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1.  Redistributions of source code must retain the above copyright
 #     notice, this list of conditions and the following disclaimer.
 # 2.  Redistributions in binary form must reproduce the above copyright
 #     notice, this list of conditions and the following disclaimer in the
 #     documentation and/or other materials provided with the distribution.
@@ skipping 54 matching lines @@
         if errors:
             self.errors.append((test_name, errors))
         self.printer.print_finished_test(source, test_name, delay, failures, errors)
 
 
 class _Worker(object):
     def __init__(self, caller, loader, webkit_finder):
         self._caller = caller
         self._loader = loader
 
-        # FIXME: unittest2 and coverage need to be in sys.path for their internal imports to work.
+        # FIXME: coverage needs to be in sys.path for its internal imports to work.
         thirdparty_path = webkit_finder.path_from_webkit_base('Tools', 'Scripts', 'webkitpy', 'thirdparty')
         if not thirdparty_path in sys.path:
             sys.path.append(thirdparty_path)
 
 
     def handle(self, message_name, source, test_name):
         assert message_name == 'test'
         result = unittest.TestResult()
         start = time.time()
         self._caller.post('started_test', test_name)
 
         # We will need to rework this if a test_name results in multiple tests.
         self._loader.loadTestsFromName(test_name, None).run(result)
         self._caller.post('finished_test', test_name, time.time() - start,
             [failure[1] for failure in result.failures], [error[1] for error in result.errors])