bug#37475: 27.0.50 bootstrap fails

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Date: Sat, 21 Sep 2019 11:07:30 +0200
> 
> Eager macro-expansion failure: (file-error "Testing file" "Permission denied" 
> "/etc/news/organization")
> 
> In toplevel form:
> gnus/deuglify.el:221:1:Error: Testing file: Permission denied, 
> /etc/news/organization
> make[3]: *** [gnus/deuglify.elc] Error 1

This comes from this part of message.el:

  (defcustom message-user-organization-file
    (let (orgfile)
      (dolist (f (list "/etc/organization"
                       "/etc/news/organization"
                       "/usr/lib/news/organization"))
        (when (file-readable-p f)
          (setq orgfile f)))
      orgfile)
    "Local news organization file."

file-readable-p is documented to "Return t if file FILENAME exists and
you can read it."  So I think Ffile_readable_p should not signal an
error if the file does not exist, it should return nil instead.