Add back support for null0 interface blackhole routes.
diff --git a/zebra/zserv.c b/zebra/zserv.c
index ae1e044..70e7672 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -1098,6 +1098,9 @@
 	    case ZEBRA_NEXTHOP_IPV6:
 	      stream_forward (s, IPV6_MAX_BYTELEN);
 	      break;
+      case ZEBRA_NEXTHOP_BLACKHOLE:
+        nexthop_blackhole_add (rib);
+        break;
 	    }
 	}
     }