Before overwriting the destination index, first let's discard its
contents.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Tested-by: Лежанкин Иван <abyss.7@gmail.com> wrote: Reviewed-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>