Improve debugging.

server.py

@@ -221,7 +221,7 @@ def main():
 
     dnshandlers = {}
     def dns_req(channel, data):
-        debug2('Incoming DNS request.\n')
+        debug2('Incoming DNS request channel=%d.\n' % channel)
         h = DnsProxy(mux, channel, data)
         handlers.append(h)
         dnshandlers[channel] = h
@@ -243,5 +243,6 @@ def main():
             now = time.time()
             for channel,h in dnshandlers.items():
                 if h.timeout < now or not h.ok:
+                    debug3('expiring dnsreqs channel=%d\n' % channel)
                     del dnshandlers[channel]
                     h.ok = False