mempool: fix mempool.has().
mempool: fix mempool.has().

decentraland/bronzeage-node,decentraland/decentraland-node,decentraland/decentraland-node,VidaID/bcoin,VidaID/bcoin,decentraland/bronzeage-node,VidaID/bcoin,decentraland/decentraland-node,decentraland/bronzeage-node