lnpeer: reestablish_channel - don't replay unacked msgs they alrdy have
lnpeer: reestablish_channel - don't replay unacked msgs they alrdy have

e.g. Alice sends upd1, upd2, upd3, commitment_signed, upd4, upd5.
Bob receives all of these; and sends a revoke_and_ack but there is
a disconnect before Alice receives the revoke_and_ack.
During reestablish, if Bob claims to have received the commitment_signed,
Alice must not replay the msgs before that; but she should replay upd4 and upd5.

pooler/electrum-ltc,pooler/electrum-ltc,vialectrum/vialectrum,spesmilo/electrum,wakiyamap/electrum-mona,wakiyamap/electrum-mona,vialectrum/vialectrum,wakiyamap/electrum-mona,wakiyamap/electrum-mona,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc,spesmilo/electrum,vialectrum/vialectrum,pooler/electrum-ltc