Built against `master` branch 801dd40666d1e6009920ad3ff755c7bb993b2a62:

If I have no wallet.dat file and run:

    bitcoind -usehd=0

A new wallet.dat file is created and an HD seed is assigned.

I see an error message in the source:

    "Error loading %s: You can't disable HD on an already existing HD wallet or create new non-HD wallets."

but that doesn't get shown because `fFirstRun` is true, and so the code which checks for `-usehd` values doesn't run.

If it's no longer possible to create non-HD wallets, specifying -usehd=0 when creating a wallet should be an error, and not get silently ignored.
nChangePosInOut = -1;
                }
                
                
                
                
                
                
                
                
                
                
                const uint32_t nSequence = coin_control.signalRbf ? MAX_BIP125_RBF_SEQUENCE : (CTxIn::SEQUENCE_FINAL - 1);
                for (const auto& coin : setCoins)
                    txNew.vin.push_back(CTxIn(coin.outpoint,CScript(),
                                              nSequence));
                
                if (!DummySignTx(txNew, setCoins)) {
                    strFailReason = _("Signing transaction failed");
                    return false;
                }
                nBytes = GetVirtualTransactionSize(txNew);
                
                for (auto& vin : txNew.vin) {
                    vin.scriptSig = CScript();
                    vin.scriptWitness.SetNull();
                }
                nFeeNeeded = GetMinimumFee(nBytes, coin_control, ::mempool, ::feeEstimator, &feeCalc);