bug#7169: cannot specify coding via dir-locals

[Glenn Morris]

Package: emacs

I added:

  (coding . utf-8)

to the change-log-mode section in the Emacs .dir-locals.el file, then did

 ./src/emacs -Q lisp/ChangeLog.1

The file was opened in undecided-unix. I was hoping to be able to
remove the "coding: utf-8" that many of the Emacs ChangeLog files
(but not that particular example) have.

It seems `find-auto-coding' handles the coding: cookie independently
of the local-variables mechanism. It would be nice if it would check
for a directory-local coding if no file-local setting is found.