Add optional locktime parameter to CreateRawTransaction APIs.

Upstream commit c560720

rawtransactions.go

@@ -240,22 +240,22 @@ func (r FutureCreateRawTransactionResult) Receive() (*wire.MsgTx, error) {
 //
 // See CreateRawTransaction for the blocking version and more details.
 func (c *Client) CreateRawTransactionAsync(inputs []dcrjson.TransactionInput,
-	amounts map[dcrutil.Address]dcrutil.Amount) FutureCreateRawTransactionResult {
+	amounts map[dcrutil.Address]dcrutil.Amount, lockTime *int64) FutureCreateRawTransactionResult {
 
 	convertedAmts := make(map[string]float64, len(amounts))
 	for addr, amount := range amounts {
 		convertedAmts[addr.String()] = amount.ToCoin()
 	}
-	cmd := dcrjson.NewCreateRawTransactionCmd(inputs, convertedAmts)
+	cmd := dcrjson.NewCreateRawTransactionCmd(inputs, convertedAmts, lockTime)
 	return c.sendCmd(cmd)
 }
 
 // CreateRawTransaction returns a new transaction spending the provided inputs
 // and sending to the provided addresses.
 func (c *Client) CreateRawTransaction(inputs []dcrjson.TransactionInput,
-	amounts map[dcrutil.Address]dcrutil.Amount) (*wire.MsgTx, error) {
+	amounts map[dcrutil.Address]dcrutil.Amount, lockTime *int64) (*wire.MsgTx, error) {
 
-	return c.CreateRawTransactionAsync(inputs, amounts).Receive()
+	return c.CreateRawTransactionAsync(inputs, amounts, lockTime).Receive()
 }
 
 // FutureCreateRawSStxResult is a future promise to deliver the result