[calligra] libs/textlayout: Fix crash on editing.

[Sebastian Sauer]

C. Boemann wrote:
> Actually this may be due to the document containing foot or endnotes
> 
> I have some trick in mind to prevent this, so are there anyway you can
> mark or move this to a workaround branch for now

I don't think that's a good idea. It's crashing just because of painting, the 
commit fixes it, the fix cannot harm. If you have a better fix please commit 
and then remove the two lines again.