This fixes warning C4458 issued by MSVC 14.0 (aka VS2015) compiler.

Change-Id: I48ed50bb54232d70460495d6d6a9e100fb90b869
Reviewed-on: https://gerrit.libreoffice.org/17444Reviewed-by: David Ostrovsky <david@ostrovsky.org>
Tested-by: David Ostrovsky <david@ostrovsky.org>