vlib: add flag to explicitelly mark nodes which can init per-node packet trace

Type: feature

Change-Id: I913f08383ee1c24d610c3d2aac07cef402570e2c
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index ad18637..891870c 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -1339,6 +1339,7 @@
 VLIB_REGISTER_NODE (session_queue_node) =
 {
   .function = session_queue_node_fn,
+  .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
   .name = "session-queue",
   .format_trace = format_session_queue_trace,
   .type = VLIB_NODE_TYPE_INPUT,