Don't even bother trying to dislay such. Any progress feedback to the
user will be handled through LibreOfficeKit callbacks.

(Sure, the code probably thought it had created a "window" for the
progress bar, but there wasn't anything real in the data structure
that would actually display anything anywhere, no CG context (on iOS)
etc.)

Change-Id: Ie0ca18bbb22da41882bdaba4a0ce77a52112a059