Don't assign any routes to interfaces that are not up.

libnetutil/netutil.cc

@@ -1523,6 +1523,8 @@ static struct dnet_collector_route_nfo *sysroutes_dnet_find_interfaces(struct dn
     /* First we match up routes whose gateway address directly matches the
        address of an interface. */
     for (j = 0; j < numifaces; j++) {
+      if (!ifaces[j].device_up)
+        continue;
       if (sockaddr_equal_netmask(&ifaces[j].addr, &dcrn->routes[i].gw, ifaces[j].netmask_bits)) {
         dcrn->routes[i].device = &ifaces[j];
         break;