Tidy up champ chooser logs.
Make counters count unchanged blocks in phase2.
Limit the number of checksums sent to the champ chooser at once, otherwise
it processes them faster than new completed manifests get to it, reducing
deduplication efficiency.
Warn if files are verified/restored from outside a hardlinked_archive.
Fix delete race conditions.
Fix another delete problem - the most recent backup was getting marked as
deletable instead of the oldest.
Finally get the server doing sensible things with the IPv4/6 listen addresses.