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

Tools/Scripts/webkitpy/layout_tests/controllers/manager_unittest.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 # Copyright (C) 2010 Gabor Rapcsanyi (rgabor@inf.u-szeged.hu), University of Szeged
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 """Unit tests for manager.py."""
 
 import sys
 import time
-import webkitpy.thirdparty.unittest2 as unittest
+import unittest
 
 from webkitpy.common.host_mock import MockHost
 from webkitpy.layout_tests.controllers.manager import Manager
 from webkitpy.layout_tests.models import test_expectations
 from webkitpy.layout_tests.models.test_run_results import TestRunResults
 from webkitpy.thirdparty.mock import Mock
 from webkitpy.tool.mocktool import MockOptions
 
 
 class ManagerTest(unittest.TestCase):
@@ skipping 66 matching lines @@
             port = host.port_factory.get('test-mac-leopard')
             manager = Manager(port, options=MockOptions(test_list=None, http=True, max_locked_shards=1), printer=Mock())
             return manager
         host = MockHost()
         port = host.port_factory.get('test-mac-leopard')
         tests = ['failures/expected/crash.html']
         expectations = test_expectations.TestExpectations(port, tests)
         run_results = TestRunResults(expectations, len(tests))
         manager = get_manager()
         manager._look_for_new_crash_logs(run_results, time.time())