Without this patch, warnings will be given 
when LibreOffice is built with JDK9 or later.

Change-Id: I7aa6e99ace2377fbdb7dd732949ce10d9bd9df58
Reviewed-on: https://gerrit.libreoffice.org/72947
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>