Use NamedTuple notation for TxOutput in test_lnchannel
Use NamedTuple notation for TxOutput in test_lnchannel

This makes the code more resilient in case additional members are added
to TxOutput later.

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