lnwallet: make SendOutputs take feerate in SatPerVByte

lnwallet/interface.go

@@ -161,9 +161,9 @@ type WalletController interface {
 	// paying out to the specified outputs. In the case the wallet has
 	// insufficient funds, or the outputs are non-standard, an error should
 	// be returned. This method also takes the target fee expressed in
-	// sat/byte that should be used when crafting the transaction.
+	// sat/vbyte that should be used when crafting the transaction.
 	SendOutputs(outputs []*wire.TxOut,
-		feeSatPerByte btcutil.Amount) (*chainhash.Hash, error)
+		feeRate SatPerVByte) (*chainhash.Hash, error)
 
 	// ListUnspentWitness returns all unspent outputs which are version 0
 	// witness programs. The 'confirms' parameter indicates the minimum