Largely reduce the number of pylint warnings and fix one typo.

drover.py

 #!/usr/bin/python
 # Copyright (c) 2010 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.
 
 import optparse
 import os
 import re
 import subprocess
 import sys
 
-import breakpad
+import breakpad  # pylint: disable=W0611
 
 import gclient_utils
 
 USAGE = """
 WARNING: Please use this tool in an empty directory
 (or at least one that you don't mind clobbering.)
 
 REQUIRES: SVN 1.5+
 NOTE: NO NEED TO CHECKOUT ANYTHING IN ADVANCE OF USING THIS TOOL."
 Valid parameters:
@@ skipping 529 matching lines @@
 
   if options.local and (options.revert or options.branch):
     option_parser.error("--local cannot be used with --revert or --branch")
     return 1
 
   return drover(options, args)
 
 
 if __name__ == "__main__":
   sys.exit(main())