cat-file: handle trivial --batch format with --batch-all-objects

The --batch code to print an object assumes we found out the type of the object from calling oid_object_info_extended(). This is true for the default format, but even in a custom format, we manually modify the object_info struct to ask for the type. This assumption was broken by 845de33a5b (cat-file: avoid noop calls to sha1_object_info_extended, 2016-05-18). That commit skips the call to oid_object_info_extended() entirely when --batch-all-objects is in use, and the custom format does not include any placeholders that require calling it. Or when the custom format only include placeholders like %(objectname) or %(rest), oid_object_info_extended() will not get the type of the object. This results in an error when we try to confirm that the type didn't change: $ git cat-file --batch=batman --batch-all-objects batman fatal: object 000023961a0c02d6e21dc51ea3484ff71abf1c74 changed type!? and also has other subtle effects (e.g., we'd fail to stream a blob, since we don't realize it's a blob in the first place). We can fix this by flipping the order of the setup. The check for "do we need to get the object info" must come _after_ we've decided whether we need to look up the type. Helped-by: Jeff King <peff@peff.net> Signed-off-by: ZheNing Hu <adlternative@gmail.com> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>