log: Fix delete log for 2038

[bmwiedemann]

code was added in commit 9b3c946

Background:
As part of my work on reproducible builds for openSUSE, I check that software still gives identical build results in the future.
The usual offset is +16 years, because that is how long I expect some software will be used in some places.
This showed up failing tests in our package build.
See https://reproducible-builds.org/ for why this matters.

[dormando]

Thanks! I wonder how difficult it would be for me to add a buildbot for this.

I'm going to merge this before the next release but leave it for a little bit so I can see about a buildbot with +16 years clock.

[bmwiedemann]

In my tests I use qemu-kvm -rtc base=2038-09-04T00:00:00 with -kernel and -initrd to run scripts without full OS services.