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.
{
    overviewAction->setChecked(true);
    if (walletFrame) walletFrame->gotoOverviewPage();
}
void BitcoinGUI::gotoHistoryPage()
{
    historyAction->setChecked(true);
    if (walletFrame) walletFrame->gotoHistoryPage();
}
void BitcoinGUI::gotoReceiveCoinsPage()
{
    receiveCoinsAction->setChecked(true);
    if (walletFrame) walletFrame->gotoReceiveCoinsPage();
}
void BitcoinGUI::gotoSendCoinsPage(QString addr)
{
    sendCoinsAction->setChecked(true);
    if (walletFrame) walletFrame->gotoSendCoinsPage(addr);
}
void BitcoinGUI::gotoSignMessageTab(QString addr)
{
    if (walletFrame) walletFrame->gotoSignMessageTab(addr);
}
void BitcoinGUI::gotoVerifyMessageTab(QString addr)