def listener_delete_event(self, listener_info):
        """Process listener delete event.

        This is lbaas v2
        vif will be plugged into ovs when first
        listener is created and unpluged from ovs
        when last listener is deleted.
        as the data only contains listener id, we will
        scan all loadbalancers from db and delete the vdp
        if their admin state is down in that loadbalancer
        """
        lb_list = self.neutronclient.list_loadbalancers()
        for lb in lb_list.get('loadbalancers'):
            if not lb.get("listeners"):
                lb_id = lb.get('id')
                LOG.info("Deleting lb %s port" % lb_id)
                self.delete_lbaas_port(lb_id)