フロー削除時のエラー対応

OpenFlow 1.3では、フロー削除時に out_port と out_group の設定が必須となります。

    out_port         For ``OFPFC_DELETE*`` commands, require matching
                     entries to include this as an output port
    out_group        For ``OFPFC_DELETE*`` commands, require matching
                     entries to include this as an output group