bitcoind won't start if datadir is specified in the conf file and the user running it has no home dir

tested with debian stretch and bitcoin 0.17.1

```
# sudo -u bitcoin bitcoind -daemon -conf=/usr/local/etc/bitcoin/bitcoin.conf -pid=/run/bitcoind/bitcoind.pid

************************
EXCEPTION: N5boost10filesystem16filesystem_errorE
boost::filesystem::create_directories: Permission denied: "/home/bitcoin"
bitcoin in AppInit()

bitcoind: chainparamsbase.cpp:29: const CBaseChainParams& BaseParams(): Assertion `globalChainBaseParams' failed.
Aborted

# mkhomedir_helper bitcoin

# sudo -u bitcoin bitcoind -daemon -conf=/usr/local/etc/bitcoin/bitcoin.conf -pid=/run/bitcoind/bitcoind.pid
Bitcoin server starting
```


{
    QSettings settings;
    
    
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    QString lang_territory_qsettings = settings.value("language", "").toString();
    if(!lang_territory_qsettings.isEmpty())
        lang_territory = lang_territory_qsettings;
    
    lang_territory = QString::fromStdString(gArgs.GetArg("-lang", lang_territory.toStdString()));
    return lang_territory;
}
static void initTranslations(QTranslator &qtTranslatorBase, QTranslator &qtTranslator, QTranslator &translatorBase, QTranslator &translator)