lnwallet: reverse order of signatures when spending the funding output

This commit is a follow up to the prior commit, as since we reversed
the order of the pubkeys in the multi-sig scripts, then we also need to
reverse the order of the signatures that we use when attempting to
spend the funding output directly.

lnwallet/script_utils.go

@@ -121,7 +121,7 @@ func SpendMultiSig(witnessScript, pubA, sigA, pubB, sigB []byte) [][]byte {
 	// public keys in descending order. So we do a quick comparison in order
 	// ensure the signatures appear on the Script Virtual Machine stack in
 	// the correct order.
-	if bytes.Compare(pubA, pubB) == -1 {
+	if bytes.Compare(pubA, pubB) == 1 {
 		witness[1] = sigB
 		witness[2] = sigA
 	} else {