Fix pylint unused-* warnings in webkitpy/tool.

third_party/WebKit/Tools/Scripts/webkitpy/tool/servers/reflectionhandler.py

 # Copyright (c) 2011 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 108 matching lines @@
         json.dump(json_object, self.wfile)
 
     def _serve_file(self, file_path, cacheable_seconds=0, headers_only=False):
         if not os.path.exists(file_path):
             self.send_error(404, "File not found")
             return
         with codecs.open(file_path, "rb") as static_file:
             self.send_response(200)
             self._send_access_control_header()
             self.send_header("Content-Length", os.path.getsize(file_path))
-            mime_type, encoding = mimetypes.guess_type(file_path)
+            mime_type, _ = mimetypes.guess_type(file_path)
             if mime_type:
                 self.send_header("Content-type", mime_type)
 
             if cacheable_seconds:
                 expires_time = (datetime.datetime.now() +
                                 datetime.timedelta(0, cacheable_seconds))
                 expires_formatted = wsgiref.handlers.format_date_time(
                     time.mktime(expires_time.timetuple()))
                 self.send_header("Expires", expires_formatted)
             self.end_headers()
 
             if not headers_only:
                 shutil.copyfileobj(static_file, self.wfile)
 
     def _serve_xml(self, xml):
         self.send_response(200)
         self._send_access_control_header()
         self.send_header("Content-type", "text/xml")
         self.end_headers()
         xml = xml.encode('utf-8')
         self.wfile.write(xml)