[2676] remove the comment about using "protected" member in __notify_update.

the revised code eliminated its use as a side effect.

src/bin/ddns/ddns.py.in

@@ -587,13 +587,6 @@ class DDNSServer:
         For a longer term we'll need to switch to asynchronous communication,
         but for now we rely on the blocking operation.
 
-        Note also that we directly refer to the "protected" member of
-        ccsession (_cc._session) rather than creating a separate channel.
-        It's probably not the best practice, but hopefully we can introduce
-        a cleaner way when we support asynchronous communication.
-        At the moment we prefer the brevity with the use of internal channel
-        of the cc session.
-
         '''
         try:
             # FIXME? Is really rpc_call the correct one? What if there are more