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.
{
    if(!walletFrame)
        return false;
    const QString name = walletModel->getWalletName();
    QString display_name = name.isEmpty() ? "["+tr("default wallet")+"]" : name;
    setWalletActionsEnabled(true);
    m_wallet_selector->addItem(display_name, name);
    if (m_wallet_selector->count() == 2) {
        m_wallet_selector_label_action->setVisible(true);
        m_wallet_selector_action->setVisible(true);
    }
    rpcConsole->addWallet(walletModel);
    return walletFrame->addWallet(walletModel);
}
bool BitcoinGUI::removeWallet(WalletModel* walletModel)
{
    if (!walletFrame) return false;
    QString name = walletModel->getWalletName();
    int index = m_wallet_selector->findData(name);
    m_wallet_selector->removeItem(index);
    if (m_wallet_selector->count() == 0) {
        setWalletActionsEnabled(false);
    } else if (m_wallet_selector->count() == 1) {
        m_wallet_selector_label_action->setVisible(false);
        m_wallet_selector_action->setVisible(false);
    }
    rpcConsole->removeWallet(walletModel);
    return walletFrame->removeWallet(name);
}
bool BitcoinGUI::setCurrentWallet(const QString& name)