ofctl_rest: Add support for strict matching

ofctl_rest is now enable to modify and delete with strict matching.

usage)

  URI:    /stats/flowentry/modify_strict
          /stats/flowentry/delete_strict

  method: POST

e.g. )

  curl -X POST -d '{"dpid": 1,
                    "actions":[{"port":3, "type":"OUTPUT"}],
                    "match":{"in_port":2}}'
                    http://localhost:8080/stats/flowentry/modify_strict

  curl -X POST -d '{"dpid": 1,
                    "match":{"in_port":2}}'
                    http://localhost:8080/stats/flowentry/delete_strict

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