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superceded by the standard: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_log b/openflow_input/bsn_log
index b2a9758..e636d6e 100644
--- a/openflow_input/bsn_log
+++ b/openflow_input/bsn_log
@@ -29,6 +29,7 @@
 // the receiver's configured loglevel is lower than the message's loglevel.
 
 #version 4
+#version 5
 
 enum ofp_bsn_loglevel(wire_type=uint8_t) {
     OFP_BSN_LOGLEVEL_MSG = 0,