vrrp: fix vrrp_garp_or_na_send()'s memory leak

need free bi after send packets

Type: fix

Signed-off-by: luoyaozu <luoyaozu@foxmail.com>
Change-Id: I98d03820366c3d106df212c4eb353ec6a228e20e

src/plugins/vrrp/vrrp_packet.c

@@ -538,6 +538,8 @@ vrrp_garp_or_na_send (vrrp_vr_t * vr)
 
   vlib_put_frame_to_node (vm, vmp->intf_output_node_idx, to_frame);
 
+  vec_free (bi);
+
   return 0;
 }