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

Tools/Scripts/webkitpy/layout_tests/port/server_process_unittest.py

 # Copyright (C) 2011 Google Inc. All rights reserved.
 #
 # 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
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 10 matching lines @@
 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # 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.
 
 import sys
 import time
-import webkitpy.thirdparty.unittest2 as unittest
+import unittest
 
 from webkitpy.layout_tests.port.factory import PortFactory
 from webkitpy.layout_tests.port import server_process
 from webkitpy.common.system.systemhost import SystemHost
 from webkitpy.common.system.systemhost_mock import MockSystemHost
 from webkitpy.common.system.outputcapture import OutputCapture
 
 
 class TrivialMockPort(object):
     def __init__(self):
@@ skipping 118 matching lines @@
 
     def test_newlines(self):
         qd = server_process.quote_data
         self.assertEqual(qd("foo \nbar\n"),
                          ["foo\x20\\n", "bar\\n"])
 
     def test_binary_data(self):
         qd = server_process.quote_data
         self.assertEqual(qd("\x00\x01ab"),
                          ["\\x00\\x01ab"])