Create a cros directory under client, and start moving things into it.

client/site_tests/login_Backdoor/login_Backdoor.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import shutil, utils
-from autotest_lib.client.bin import chromeos_constants, site_login, site_ui_test
+from autotest_lib.client.bin import site_login, site_ui_test
 from autotest_lib.client.common_lib import site_auth_server
 
 class login_Backdoor(site_ui_test.UITest):
     version = 1
 
 
     def __login_denier(self, handler, url_args):
         handler.send_response(403)
         handler.end_headers()
         handler.wfile.write('Error=BadAuthentication.')
 
 
     def start_authserver(self):
         self._authServer = site_auth_server.GoogleAuthServer(
             cl_responder=self.__login_denier)
         self._authServer.run()
 
         self.use_local_dns()
 
 
     def run_once(self):
         pass