fix crash when parsing payment with tx return at the end
fix crash when parsing payment with tx return at the end

you21979/NBitcoin,bitcoinbrisbane/NBitcoin,dangershony/NStratis,NicolasDorier/NBitcoin,stratisproject/NStratis,MetacoSA/NBitcoin,lontivero/NBitcoin,MetacoSA/NBitcoin,HermanSchoenfeld/NBitcoin,thepunctuatedhorizon/BrickCoinAlpha.0.0.1