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 (dbw) {
            return dbw->GetName();
        } else {
            return "dummy";
        }
    }
    void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool);
    
    
    std::map<CTxDestination, CKeyMetadata> mapKeyMetadata;
    typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
    MasterKeyMap mapMasterKeys;
    unsigned int nMasterKeyMaxID;
    
    CWallet(): dbw(new CWalletDBWrapper())
    {
        SetNull();
    }
    
    explicit CWallet(std::unique_ptr<CWalletDBWrapper> dbw_in) : dbw(std::move(dbw_in))
    {
        SetNull();
    }
    ~CWallet()
    {
        delete pwalletdbEncryption;
        pwalletdbEncryption = nullptr;
    }
    void SetNull()