Tweak heuristics for legacy peers.

message.c

@@ -394,8 +394,8 @@ parse_packet(const unsigned char *from, struct network *net,
             } else {
                 int l = 10 + (message[4] + 7) / 8 - message[5];
                 /* If the peer doesn't send diversity information,
-                   assume that routes with a zero metric are non-interfering. */
-                if(metric == 0) {
+                   assume that routes with a small metric are non-interfering. */
+                if(metric <= 192) {
                     channels[0] = 0;
                 } else {
                     channels[0] = NET_CHANNEL_INTERFERING;