1. Return error if any step of generating tar file fails
2. Use pipefail to avoid calling "gzip" if tar failed
Fixes: e36cc530927c ("base-files: sysupgrade: use tar helper to include installed_packages.txt")
Reported-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>