So that a modification will result in an invalid signature.

Change-Id: Ib40e0b941d56e29c134993e1d41f496aa183bd7f
Reviewed-on: https://gerrit.libreoffice.org/55079Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>