bug#24394: 25.1.50; (find-file "/sudo::") ignores async-shell-command-buffer settings

[Tino Calancha <tino.calancha@gmail.com>]

emacs -Q -eval "(setq async-shell-command-buffer 'new-buffer)"

I) M-&: i=0; while true; do echo $i; i=$((i+1)); sleep 1;done RET
;; Repeating the command will not prompt for confirmation
II) M-&: M-p RET ; create buffer "*Async Shell Command*<2>".
III) M-:(let ((dir (expand-file-name default-directory)))
           (find-file (concat "/sudo::") dir)) RET
IV) M-&: M-p RET
;; Received prompt to kill buffer "*Async Shell Command*".

In IV) the machine is the same as before and the original user
still is the owner of the Emacs session: i would expect IV) create
the buffer "*Async Shell Command*<3>" without any prompt.
Even if i set `async-shell-command-buffer' to 'new-buffer in
/root/.emacs i receive the prompt.


In GNU Emacs 25.1.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.21.5)
  of 2016-09-08
Repository revision: ba5d32398ba42fcf14ad5242d95c68133981744f