KIO::mimetype sync call in DocumentController::openDocumentInternal hazardous

[Niko Sams]

> So how can we fix this? Can someone explain how I could make
> openDocumentInternal reentrant? Just by coping with the case the assertion
> currently prevents? I sadly don't see a way to use the safe async KJob api
> here :-S
Can you add a callback function that asynchronously gets called when the
job finished and continues then with openDocument?
Yes, that would make the code quite complicated.

Niko