create a LACP packet.

def _create_lacp(self, datapath, port, req):
        """create a LACP packet."""
        actor_system = datapath.ports[datapath.ofproto.OFPP_LOCAL].hw_addr
        res = slow.lacp(
            actor_system_priority=0xffff,
            actor_system=actor_system,
            actor_key=req.actor_key,
            actor_port_priority=0xff,
            actor_port=port,
            actor_state_activity=req.LACP_STATE_PASSIVE,
            actor_state_timeout=req.actor_state_timeout,
            actor_state_aggregation=req.actor_state_aggregation,
            actor_state_synchronization=req.actor_state_synchronization,
            actor_state_collecting=req.actor_state_collecting,
            actor_state_distributing=req.actor_state_distributing,
            actor_state_defaulted=req.LACP_STATE_OPERATIONAL_PARTNER,
            actor_state_expired=req.LACP_STATE_NOT_EXPIRED,
            partner_system_priority=req.actor_system_priority,
            partner_system=req.actor_system,
            partner_key=req.actor_key,
            partner_port_priority=req.actor_port_priority,
            partner_port=req.actor_port,
            partner_state_activity=req.actor_state_activity,
            partner_state_timeout=req.actor_state_timeout,
            partner_state_aggregation=req.actor_state_aggregation,
            partner_state_synchronization=req.actor_state_synchronization,
            partner_state_collecting=req.actor_state_collecting,
            partner_state_distributing=req.actor_state_distributing,
            partner_state_defaulted=req.actor_state_defaulted,
            partner_state_expired=req.actor_state_expired,
            collector_max_delay=0)
        self.logger.info("SW=%s PORT=%d LACP sent.",
                         dpid_to_str(datapath.id), port)
        self.logger.debug(str(res))
        return res