Again, dumb transport clients are too dumb to make use of the
top objects information to make a choice among multiple packs,
so computing these lines are useless for now.  We could
resurrect them if needed later.  Also dumb transport clients
presumably can do their own approximation by downloading idx
files to see how relevant each pack is for their fetch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>