A hello world ODT is now exported without validation errors.

Change-Id: I2b160ee980f8ed9c80fd76945600d1edb1ee29bc
Reviewed-on: https://gerrit.libreoffice.org/40908Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>