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.
if (!ret)
                {
                    strFailReason = _("Keypool ran out, please call keypoolrefill first");
                    return false;
                }
                scriptChange = GetScriptForDestination(vchPubKey.GetID());
            }
            CTxOut change_prototype_txout(0, scriptChange);
            size_t change_prototype_size = GetSerializeSize(change_prototype_txout, SER_DISK, 0);
            CFeeRate discard_rate = GetDiscardRate(::feeEstimator);
            nFeeRet = 0;
            bool pick_new_inputs = true;
            CAmount nValueIn = 0;
            
            while (true)
            {
                nChangePosInOut = nChangePosRequest;
                txNew.vin.clear();
                txNew.vout.clear();
                wtxNew.fFromMe = true;
                bool fFirst = true;
                CAmount nValueToSelect = nValue;
                if (nSubtractFeeFromAmount == 0)
                    nValueToSelect += nFeeRet;
                
                for (const auto& recipient : vecSend)
                {
                    CTxOut txout(recipient.nAmount, recipient.scriptPubKey);
                    if (recipient.fSubtractFeeFromAmount)
                    {