htlcswitch: remove unused NewSphinxBlob function
htlcswitch: remove unused NewSphinxBlob function

LightningNetwork/lnd,LightningNetwork/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,ddustin/lnd,aakselrod/lnd,aakselrod/lnd,AndrewSamokhvalov/lnd