bug#24317: 25.1.50; image-dired-rotate-original: regexp doesn't match .jpeg suffix

[Eli Zaretskii]

> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sat, 27 Aug 2016 17:04:01 +0900 (JST)
> 
> >From 4ea0333150937d3f2f615df1ed476e6279caf77b Mon Sep 17 00:00:00 2001
> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sat, 27 Aug 2016 16:53:37 +0900
> Subject: [PATCH] image-dired-rotate-original: regexp doesn't match .jpeg
>   suffix
> 
> * lisp/image-dired.el (image-dired-jpeg-suffix-regexp): New defvar.
> (image-dired-rotate-original, image-dired-get-exif-file-name):
> Use it (Bug#24317).

I understand why we need to fix a typo in the regexp (which the log
entry doesn't even mention, btw), but what's the rationale for making
it a defvar?

Thanks.