Previously, prune treated an expiration time of 0 to mean that no
expire argument was supplied, and everything should be pruned. As a
result, "prune --expire=never" would prune all unreachable objects,
regardless of their timestamp.
prune can be called with --expire=never automatically by gc, when the
gc.pruneExpire configuration is set to "never".
Signed-off-by: Adam Simpkins <simpkins@facebook.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>