zebra: match gateway when deleting NEXTHOP_IPV4_IFINDEX routes

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Acked-by: Feng Lu <lu.feng@6wind.com>
diff --git a/zebra/zserv.c b/zebra/zserv.c
index 5df521b..55ac6e4 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -879,6 +879,7 @@
 	      break;
 	    case ZEBRA_NEXTHOP_IPV4_IFINDEX:
 	      nexthop.s_addr = stream_get_ipv4 (s);
+	      nexthop_p = &nexthop;
 	      ifindex = stream_getl (s);
 	      break;
 	    case ZEBRA_NEXTHOP_IPV6: