Fix missing strFailReason in CreateTransaction

Suggested by MarcoFalke <[email protected]>
bitcoin/bitcoin#17260 (comment)

Author: ryanofsky

src/wallet/wallet.cpp

@@ -2783,11 +2783,7 @@ bool CWallet::CreateTransaction(interfaces::Chain::Lock& locked_chain, const std
                 SignatureData sigdata;
 
                 const SigningProvider* provider = GetSigningProvider();
-                if (!provider) {
-                    return false;
-                }
-
-                if (!ProduceSignature(*provider, MutableTransactionSignatureCreator(&txNew, nIn, coin.txout.nValue, SIGHASH_ALL), scriptPubKey, sigdata))
+                if (!provider || !ProduceSignature(*provider, MutableTransactionSignatureCreator(&txNew, nIn, coin.txout.nValue, SIGHASH_ALL), scriptPubKey, sigdata))
                 {
                     strFailReason = _("Signing transaction failed").translated;
                     return false;