A bit of buffer metadata reshuffling to accommodate flow_id

Change-Id: I2794384557c6272fe217269b14a9db09eda19220
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/pg/input.c b/src/vnet/pg/input.c
index 1cbffed..a743082 100644
--- a/src/vnet/pg/input.c
+++ b/src/vnet/pg/input.c
@@ -1523,7 +1523,7 @@
 	      s->next_index;
 	    vnet_buffer (b)->device_input_feat.buffer_advance = 0;
 	    b->current_config_index = current_config_index;
-	    b->feature_arc_index = feature_arc_index;
+	    vnet_buffer (b)->feature_arc_index = feature_arc_index;
 	  }
 
       n_trace = vlib_get_trace_count (vm, node);