bs_published_hook_aptly_snapshot: Don't generate latest snapshot symlink

We don't use the latest symlink, just the latest.txt timestamp. So drop
it.

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
4 jobs for wip/adalessandro/aptly-snapshot-prefixdistro in 15 minutes and 27 seconds (queued for 4 seconds)