vcl: fixup svdemo

Change-Id: Ifb7cc12da349fcbcd1d3dc25b64cd2bf3fd7e819
Reviewed-on: https://gerrit.libreoffice.org/9378
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>