bug#23823: 25.0.95; Reset between highlight buffer/file comparisons

[Eli Zaretskii]

> From: Tino Calancha <f92capac@gmail.com>
> Date: Wed, 22 Jun 2016 19:11:27 +0900 (JST)
> 
> ./emacs -r -Q -eval '(progn (with-temp-file "/tmp/foo" (insert "foo")) 
> (switch-to-buffer "bar") (insert "boo"))'
> M-: (highlight-compare-with-file "/tmp/foo") RET
> C-b C-b DEL f
> M-: M-p RET
> ;; Now current buffer content equals /tmp/foo content
> ;; but foo is still displayed with face highlight-changes.

What I see is 'f' in a "deleted" face.  Which seems reasonable to me.

Whether a change that countermands another change should count as a
change is a philosophical question that AFAIK doesn't have a
one-fits-all answer.