When using a TerminationVetoException, all windows should be closed,
but the process should be kept running.

Change-Id: I71b0b57b6035a36f0325c8dea3cd38309408f176
Reviewed-on: https://gerrit.libreoffice.org/29031Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>