wallet: log when saving already paid invoice
wallet: log when saving already paid invoice

(maybe it should not be allowed?)

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