adjust PackageInfo for zip files

see commit 7fe9808f009af2f0a4da58663eacd2caccdcaafe for reference

Change-Id: I060021150f8ef976ffeb417b18dda31367e549b8
Reviewed-on: https://gerrit.libreoffice.org/7975
Reviewed-by: Matúš Kukan <matus.kukan@collabora.com>
Tested-by: Matúš Kukan <matus.kukan@collabora.com>