Fix pylint unused-* warnings in webkitpy/tool.

third_party/WebKit/Tools/Scripts/webkitpy/tool/bot/commitannouncer.py

 # Copyright (C) 2013 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 70 matching lines @@
 
     def help(self):
         self._post('Commands available: %s' % ' '.join(self.commands.keys()))
 
     def ping(self):
         self._post('Pong.')
 
     def stop(self, message=""):
         self.connection.execute_delayed(0, lambda: self.die(message))
 
-    # IRC event handlers.
+    # IRC event handlers. Methods' arguments are determined by superclass
+    # and some arguments maybe unused - pylint: disable=unused-argument
 
     def on_nicknameinuse(self, connection, event):
         connection.nick('%s_' % connection.get_nickname())
 
     def on_welcome(self, connection, event):
         connection.join(channel)
 
     def on_pubmsg(self, connection, event):
         message = event.arguments()[0]
         command = self._message_command(message)
@@ skipping 89 matching lines @@
     def __init__(self, tool, announce_path, irc_password):
         threading.Thread.__init__(self)
         self.bot = CommitAnnouncer(tool, announce_path, irc_password)
 
     def run(self):
         self.bot.start()
 
     def stop(self):
         self.bot.stop()
         self.join()