ip6: ip6_not_enabled_node is a sibling of ip6-drop

The node ip6_not_enabled should be marked as sibling of
ip6-drop as both are start nodes of the ip6-drop arc.

Type: fix
Signed-off-by: Paul Atkins <patkins@graphiant.com>
Change-Id: I212c25444a81b11d8085ba7930ddb67b47502d5c
diff --git a/src/vnet/ip/ip6_punt_drop.c b/src/vnet/ip/ip6_punt_drop.c
index 4edb673..ab5203d 100644
--- a/src/vnet/ip/ip6_punt_drop.c
+++ b/src/vnet/ip/ip6_punt_drop.c
@@ -146,15 +146,11 @@
   },
 };
 
-VLIB_REGISTER_NODE (ip6_not_enabled_node) =
-{
+VLIB_REGISTER_NODE (ip6_not_enabled_node) = {
   .name = "ip6-not-enabled",
   .vector_size = sizeof (u32),
   .format_trace = format_ip6_forward_next_trace,
-  .n_next_nodes = 1,
-  .next_nodes = {
-    [0] = "error-drop",
-  },
+  .sibling_of = "ip6-drop",
 };
 
 VLIB_REGISTER_NODE (ip6_punt_node) =