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.
{
    std::map<CTxDestination, CAmount> balances;
    {
        LOCK(cs_wallet);
        for (const auto& walletEntry : mapWallet)
        {
            const CWalletTx *pcoin = &walletEntry.second;
            if (!pcoin->IsTrusted())
                continue;
            if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0)
                continue;
            int nDepth = pcoin->GetDepthInMainChain();
            if (nDepth < (pcoin->IsFromMe(ISMINE_ALL) ? 0 : 1))
                continue;
            for (unsigned int i = 0; i < pcoin->tx->vout.size(); i++)
            {
                CTxDestination addr;
                if (!IsMine(pcoin->tx->vout[i]))
                    continue;
                if(!ExtractDestination(pcoin->tx->vout[i].scriptPubKey, addr))
                    continue;
                CAmount n = IsSpent(walletEntry.first, i) ? 0 : pcoin->tx->vout[i].nValue;
                if (!balances.count(addr))
                    balances[addr] = 0;