Noticed this error while webkitbot was trying to revert old commit (containing changelog).

Traceback (most recent call last):
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkit-patch", line 80, in <module>
    main()
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkit-patch", line 75, in main
    WebKitPatch(os.path.abspath(__file__)).main()
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkitpy/tool/multicommandtool.py", line 305, in main
    result = command.check_arguments_and_execute(options, args, self)
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkitpy/tool/multicommandtool.py", line 123, in check_arguments_and_execute
    return self.execute(options, args, tool) or 0
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkitpy/tool/commands/abstractsequencedcommand.py", line 55, in execute
    self._sequence.run_and_handle_errors(tool, options, state)
  File "/var/lib/webkitbot/BotWebKit/Tools/Scripts/webkitpy/tool/commands/stepsequence.py", line 85, in run_and_handle_errors
    command.handle_script_error(tool, state, e)
AttributeError: 'NoneType' object has no attribute 'handle_script_error'