A particularly bad case was HASH_LIMIT <= hash_count[i] < 2*HASH_LIMIT:
in that case, only a single hash survived. For larger cases,
2*HASH_LIMIT was the actual limiting value after pruning.
Signed-off-by: David Kastrup <dak@gnu.org> Acked-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>