ofctl_v1_2/3: MAC arbitrary bitmask support

ofctl_rest is now enabled to use MAC arbitrary bitmask as follows:

  curl -X POST -d '{"dpid": 1,
                    "actions":[{"port":2, "type":"OUTPUT"}],
                    "match":{"dl_dst":"01:02:03:ab:cd:ef/ff:ff:ff:ff:00:00"}}' http://localhost:8080/stats/flowentry/add

And now enabled to display as follows:

  curl http://localhost:8080/stats/flow/1
    {
      "1": [
        {
          "actions": ["OUTPUT:2"],
          "idle_timeout": 0,
          "cookie": 0,
          "packet_count": 0,
          "hard_timeout": 0,
          "byte_count": 0,
          "duration_nsec": 951000000,
          "priority": 0,
          "duration_sec": 35,
          "table_id": 0,
          "match": {"dl_dst": "01:02:03:ab:00:00/ff:ff:ff:ff:00:00"}
        }
      ]
    }

Signed-off-by: TAKAHASHI Minoru <takahashi.minoru7@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>