message: Remove unused dummy_tx variable from FillPSBT
diff: @@ -4544,11 +4544,6 @@ bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, const C
  const CTxOut& out = txConst->vout.at(i);
  PSBTOutput& psbt_out = psbtx.outputs.at(i);
  - // Dummy tx so we can use ProduceSignature to get stuff out
  - CMutableTransaction dummy_tx;
  - dummy_tx.vin.push_back(CTxIn());
  - dummy_tx.vout.push_back(CTxOut());
  -
  // Fill a SignatureData with output info
  SignatureData sigdata;
  psbt_out.FillSignatureData(sigdata);
  