I've cleaned older packages from the archive, but sometimes we do not
rebuild packages in a long long time. We still keep have them in the
repository, but this check does not look for the package there, thus
when trying to db-update, the user sees an error. We fix this by also
looking at currently live packages instead of only relying on the
archive.

This is mostly a hotfix until a better solution is created. Depending on
when/how the ftpdir-cleanup cronjob removes such packages, users may
still see errors when an old package is updated and the cronjob removes
it from the repository before db-update is run.

Signed-off-by: Florian Pritz <bluewind@xinu.at>