Backport v2020: Fix upower startup on empty /var
Backport https://gitlab.apertis.org/pkg/target/upower/-/merge_requests/2 to v2020-updates
as it affects the OSTree images and nobody stumbled on it only by chance:
- apertis/Let-systemd-create-var-lib-upower.patch:
- Added: Backported patch from upstream to let systemd create /var/lib/upower on start to fix startup on systems with an empty /var