hgweb: drop use of super() for Exception base class

In Python 2.4, Exception is an old-style class and doesn't work with super.

mercurial/hgweb/common.py

@@ -73,7 +73,7 b' class ErrorResponse(Exception):'
     def __init__(self, code, message=None, headers=[]):
         if message is None:
             message = _statusmessage(code)
-        super(Exception, self).__init__()
+        Exception.__init__(self)
         self.code = code
         self.message = message
         self.headers = headers