Following https://cgit.freedesktop.org/libreoffice/core/commit/?id=8228227168a7eb3ebf14629bec87f01536c23970
an OSL_ENSURE has been replaced by an assert
I expect to find a bunch of these cases, so this one is the first I deal with.

Change-Id: If2d3c2f5cff9d306918adc200146113eb54f26c8
Reviewed-on: https://gerrit.libreoffice.org/31841Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>