[REVIEW 3-6-3][REVIEWED 3-6] Simple missing null object check to fix crasher.

[Markus Mohrhard]

Hey Kohei

>
> http://cgit.freedesktop.org/libreoffice/core/commit/?id=fb1d9cc99e026ba9cf15ab49b2251cecfbbf6d10
>
> backported to the 3-6 branch.  Without this check, importing the following
> document
>
> http://www.bedrunecka.cz/epd/3_naklady_a_kalkulace.ppt
>
> will crash soffice.
>
> I think the change is simple enough to be backported safely.
>

I agree and pushed to 3-6 with my sign-off. I'D like to see this patch
also in 3-6-3 so we need two more sign-offs for it.

Regards,
Markus