bug#15322: VC log buffer scrolls itself

[Eli Zaretskii <eliz@gnu.org>]

> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Sun, 03 May 2015 06:32:37 +0300
> Cc: 15322@debbugs.gnu.org
> 
> @@ -2263,8 +2264,10 @@ earlier revisions.  Show up to LIMIT entries (non-nil means unlimited)."
>       (let ((inhibit-read-only t))
>         (funcall setup-buttons-func backend files retval)
>         (shrink-window-if-larger-than-buffer)
> -       (funcall goto-location-func backend)
> -       (setq vc-sentinel-movepoint (point))
> +       ;; Bug#15322
> +       (when goto-location-func
> +         (funcall goto-location-func backend)
> +         (setq vc-sentinel-movepoint (point)))

I don't think it's a good idea to have in the code comments that only
mention the bug number, without also trying to explain the reason(s)
for what the code does.  If it's possible to write a clear and concise
explanation, you don't even need to mention the bug number.  If the
reasons are so complex that they cannot be explained without repeating
too much of the bug discussion, then there should be a summary and a
pointer to the bug.

Thanks.