Invalid characters for a wallet name, e.g. `bitcoin-qt -wallet=你好` used to result in an error like this

<img width="494" alt="schermafbeelding 2018-07-24 om 17 46 37" src="https://user-images.githubusercontent.com/10217/43150553-7bdf598a-8f6a-11e8-8972-44c311a57e56.png">

But now it just crashes:

<img width="509" alt="schermafbeelding 2018-07-24 om 17 43 26" src="https://user-images.githubusercontent.com/10217/43150605-9cf32192-8f6a-11e8-9333-87d074c8dd35.png">

I didn't do a `git bisect`, but it broke somewhere this year :-)
continue;
        }
        else if (!(fIsMine & filter))
            continue;
        
        CTxDestination address;
        if (!ExtractDestination(txout.scriptPubKey, address) && !txout.scriptPubKey.IsUnspendable())
        {
            LogPrintf("CWalletTx::GetAmounts: Unknown transaction type found, txid %s\n",
                     this->GetHash().ToString());
            address = CNoDestination();
        }
        COutputEntry output = {address, txout.nValue, (int)i};
        
        if (nDebit > 0)
            listSent.push_back(output);
        
        if (fIsMine & filter)
            listReceived.push_back(output);
    }
}
/**
 * Scan active chain for relevant transactions after importing keys. This should
 * be called whenever new keys are added to the wallet, with the oldest key
 * creation time.
 *
 * @return Earliest timestamp that could be successfully scanned from. Timestamp
 * returned will be higher than startTime if relevant blocks could not be read.
 */
int64_t CWallet::RescanFromTime(int64_t startTime, const WalletRescanReserver& reserver, bool update)