Since 052fe5ea (sha1_loose_object_info: make type lookup optional,
2013-07-12), sha1_loose_object_info() returns happily without
checking if the object in question exists, which is not what the the
caller sha1_object_info_extended() expects; the caller does not even
bother checking the existence of the object itself.
Noticed-by: NSven Brauch <svenbrauch@googlemail.com>
Helped-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>