misc: fix api in ipfix_classify_table_add/details

misc: fix api in ipfix_classify_table_add/details

In ipfix_classify_table_add_del and ipfix_classify_table_details the
ip_version field has vl_api_address_family_t type. However, there is
no encode/decode for the field in the IPFIX API. Moreover, the IPFIX
code expects the field to contain raw 4 or 6 to indicate the IP
version.

With this change, encode/decode the ip_version field in the IPFIX
API. Also, stop converting transport_protocol between host and network
byte order because it's u8.

Type: fix
Signed-off-by: Alexander Chernavin <achernavin@netgate.com>
Change-Id: I4051756b8077b4367dd779cb555a34f74f6d7a9d