Make sure all tests for void neighbours use FF.

babel.c

@@ -633,7 +633,7 @@ dump_tables(FILE *out)
     }
 
     for(i = 0; i < numneighs; i++) {
-        if(neighs[i].id[0] == 0)
+        if(neighs[i].id[0] == 0xFF)
             continue;
         fprintf(out, "Neighbour %s ", format_address(neighs[i].id));
         fprintf(out, "at %s dev %s reach %04x rxcost %d txcost %d.\n",
@@ -739,7 +739,7 @@ expire_routes(void)
     debugf("Expiring old routes.\n");
 
     for(i = 0; i < numneighs; i++) {
-        if(neighs[i].id[0] == 0)
+        if(neighs[i].id[0] == 0xFF)
             continue;
         check_neighbour(&neighs[i]);
         /* No need to update_neighbour_metric -- update_route_metric below. */

message.c

@@ -719,7 +719,7 @@ send_txcost(struct neighbour *neigh, struct network *net)
             schedule_flush(net);
         } else {
             for(i = 0; i < numneighs; i++) {
-                if(neighs[i].id[0] != 0) {
+                if(neighs[i].id[0] != 0xFF) {
                     if(neighs[i].network == net)
                         send_txcost(&neighs[i], net);
                 }