The Massif tool of Valgrind revealed that parsed tree entries occupy
more than 60% of memory allocated by git-fsck-objects. These entries
can be freed immediately after use, which significantly decreases
memory consumption.
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru> Signed-off-by: Junio C Hamano <junkio@cox.net>