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 (!MoneyRange(txout.nValue))
        throw std::runtime_error(std::string(__func__) + ": value out of range");
    return (IsChange(txout) ? txout.nValue : 0);
}
bool CWallet::IsMine(const CTransaction& tx) const
{
    for (const CTxOut& txout : tx.vout)
        if (IsMine(txout))
            return true;
    return false;
}
bool CWallet::IsFromMe(const CTransaction& tx) const
{
    return (GetDebit(tx, ISMINE_ALL) > 0);
}
CAmount CWallet::GetDebit(const CTransaction& tx, const isminefilter& filter) const