openflow_input: add BSN extensions to OF 1.4

I left out the following extensions that are no longer used or have been
superceded by the standard:

 - bsn_disable_split_horizon_check
 - bsn_role_status
 - bsn_global_vrf_allowed
diff --git a/openflow_input/bsn_aux_cxns b/openflow_input/bsn_aux_cxns
index 247f81b..8ceaa72 100644
--- a/openflow_input/bsn_aux_cxns
+++ b/openflow_input/bsn_aux_cxns
@@ -28,6 +28,8 @@
 // Request that the switch spawn and configure auxiliary OF connections.
 //
 #version 4
+#version 5
+
 // Set the number of desired aux connections num_aux=(0-16) accompanying this main connection
 // This message is only allowed on the main connection. 
 struct of_bsn_set_aux_cxns_request : of_bsn_header {