ofctl_v1_2/3: support setting the oxm_value to OFPVID_NONE and OFPVID_PRESENT

ofctl_v1_2/3 is now enabled to setting the oxm_value
to OFPVID_NONE(0x0000) and OFPVID_PRESENT(0x1000/0x1000) as follows:

  curl -X POST -d '{"dpid": 3,
                    "actions":[{"port":2, "type":"OUTPUT"}],
                    "match":{"dl_vlan":"OFPVID_NONE"}}' http://localhost:8080/stats/flowentry/add

  curl -X POST -d '{"dpid": 3,
                    "actions":[{"port":2, "type":"OUTPUT"}],
                    "match":{"dl_vlan":"OFPVID_PRESENT"}}' http://localhost:8080/stats/flowentry/add

Signed-off-by: Minoru TAKAHASHI <takahashi.minoru7@gmail.com>
[pre]Add test for setting the oxm_value to OFPVID_NONE and OFPVID_PRESENT

Signed-off-by: Minoru TAKAHASHI <takahashi.minoru7@gmail.com>