Make traffic shaping work when WPR chooses the server ports.

dnsproxy.py

 #!/usr/bin/env python
 # Copyright 2010 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
@@ skipping 257 matching lines @@
     """
     try:
       SocketServer.ThreadingUDPServer.__init__(
           self, (host, port), UdpDnsHandler)
     except socket.error, (error_number, msg):
       if error_number == errno.EACCES:
         raise DnsProxyException(
             'Unable to bind DNS server on (%s:%s)' % (host, port))
       raise
     self.dns_lookup = dns_lookup or (lambda host: self.server_address[0])
+    self.server_port = self.server_address[1]
     logging.warning('DNS server started on %s:%d', self.server_address[0],
                                                    self.server_address[1])
 
   def cleanup(self):
     try:
       self.shutdown()
     except KeyboardInterrupt, e:
       pass
     logging.info('Stopped DNS server')