Noticed this while reviewing #13529, but it's also in master @ 5ba77df15. On macOS 10.13.6:

```
bitcoin-qt -disablewallet
```

<img width="1354" alt="schermafbeelding 2018-08-01 om 16 03 41" src="https://user-images.githubusercontent.com/10217/43526506-b23264d8-95a4-11e8-81a0-5debcad838ae.png">

The usual progress modal doesn't appear when QT starts, and clicking on the progress bar has no effect. It works fine when there's a wallet present.
QMainWindow(parent),
    m_node(node),
    platformStyle(_platformStyle)
{
    QSettings settings;
    if (!restoreGeometry(settings.value("MainWindowGeometry").toByteArray())) {
        
        move(QApplication::desktop()->availableGeometry().center() - frameGeometry().center());
    }
    QString windowTitle = tr(PACKAGE_NAME) + " - ";
#ifdef ENABLE_WALLET
    enableWallet = WalletModel::isWalletEnabled();
#endif 
    if(enableWallet)
    {
        windowTitle += tr("Wallet");
    } else {
        windowTitle += tr("Node");
    }
    windowTitle += " " + networkStyle->getTitleAddText();
    QApplication::setWindowIcon(networkStyle->getTrayAndWindowIcon());