Run pychecker over most scripts in depot_tools. Catched a few bugs.

tests/gcl_unittest.py

 #!/usr/bin/python
 # Copyright (c) 2009 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.
 
 """Unit tests for gcl.py."""
 
 import unittest
 
 # Local imports
@@ skipping 40 matching lines @@
       'GetFilesNotInCL', 'GetInfoDir', 'GetIssueDescription',
       'GetModifiedFiles', 'GetRepositoryRoot',
       'GetSVNFileProperty', 'Help', 'IsSVNMoved',
       'Lint', 'LoadChangelistInfoForMultiple',
       'MISSING_TEST_MSG', 'Opened', 'OptionallyDoPresubmitChecks',
       'PresubmitCL', 'ReadFile', 'REPOSITORY_ROOT', 'RunShell',
       'RunShellWithReturnCode', 'SendToRietveld', 'TryChange',
       'UnknownFiles', 'UploadCL', 'Warn', 'WriteFile',
       'gclient_scm', 'gclient_utils', 'getpass', 'main', 'os', 'random', 're',
       'shutil', 'string', 'subprocess', 'sys', 'tempfile',
-      'upload', 'urllib2', 'xml',
+      'upload', 'urllib2',
     ]
     # If this test fails, you should add the relevant test.
     self.compareMembers(gcl, members)
 
   def testIsSVNMoved(self):
     # TODO(maruel): TEST ME
     pass
 
   def testGetSVNFileProperty(self):
     # TODO(maruel): TEST ME
@@ skipping 286 matching lines @@
     gcl.os.chdir('somewhere')
     self.mox.ReplayAll()
 
     gcl.UploadCL(change_info, args)
     self.assertEquals(change_info.issue, 1)
     self.assertEquals(change_info.patchset, 2)
 
 
 if __name__ == '__main__':
   unittest.main()