Sync with builtin-fetch--tool.c where append_fetch_head()
honors update_local_ref() return value.
This fixes non fast forward fetch exit status,
http://bugzilla.altlinux.org/show_bug.cgi?id=15037
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
