Do not reply to mismatched IP in confluent search

If an OS queries for confluent, but will not have a viable address,
avoid replying to let more usable network paths prevail.

For example, one OS was coming up with 169.254 with no dhcp server,
and being told it could do well to talk to 172.29, which obviously
would not work.

confluent_server/confluent/discovery/protocols/ssdp.py

@@ -202,6 +202,8 @@ def snoop(handler, byehandler=None, protocol=None, uuidlookup=None):
                                                 cfg, node, ifidx=iface)
                                             if ncfg.get('matchesnodename', None):
                                                 reply += 'DEFAULTNET: 1\r\n'
+                                        elif not netutil.address_is_local(peer[0]):
+                                            continue
                                         if not isinstance(reply, bytes):
                                             reply = reply.encode('utf8')
                                         s.sendto(reply, peer)