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superceded by the standard: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_pktin_flag b/openflow_input/bsn_pktin_flag
index fd94a49..71a4be1 100644
--- a/openflow_input/bsn_pktin_flag
+++ b/openflow_input/bsn_pktin_flag
@@ -26,6 +26,7 @@
 // under the EPL.
 
 #version 4
+#version 5
 
 // In a realistic switch pipeline there are multiple reasons a given packet
 // should be sent to the controller. The packet-in reason field is only 8 bits,