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.
{
    {
        LOCK(cs_wallet); 
        
        std::string strAddress = EncodeDestination(address);
        for (const std::pair<std::string, std::string> &item : mapAddressBook[address].destdata)
        {
            CWalletDB(*dbw).EraseDestData(strAddress, item.first);
        }
        mapAddressBook.erase(address);
    }
    NotifyAddressBookChanged(this, address, "", ::IsMine(*this, address) != ISMINE_NO, "", CT_DELETED);
    CWalletDB(*dbw).ErasePurpose(EncodeDestination(address));
    return CWalletDB(*dbw).EraseName(EncodeDestination(address));
}
const std::string& CWallet::GetAccountName(const CScript& scriptPubKey) const