find_deltas() should free its temporary objects before returning.

[jc: Sergey, if you have [PATCH] title on the Subject line of your
e-mail, please do not repeat it on the first line in your message
body.  Thanks.]
Signed-off-by: NSergey Vlasov <vsu@altlinux.ru>
Signed-off-by: NJunio C Hamano <junkio@cox.net>