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.
{
    DBErrors nZapWalletTxRet = CWalletDB(*dbw,"cr+").ZapWalletTx(vWtx);
    if (nZapWalletTxRet == DB_NEED_REWRITE)
    {
        if (dbw->Rewrite("\x04pool"))
        {
            LOCK(cs_wallet);
            setInternalKeyPool.clear();
            setExternalKeyPool.clear();
            m_pool_key_to_index.clear();
            
            
            
        }
    }
    if (nZapWalletTxRet != DB_LOAD_OK)
        return nZapWalletTxRet;
    return DB_LOAD_OK;
}
bool CWallet::SetAddressBook(const CTxDestination& address, const std::string& strName, const std::string& strPurpose)