equals -> file-equal-p refactor

Use more reliable file comparison function.

core/autoload/files.el

@@ -49,8 +49,7 @@
       (make-directory new-path-dir t))
     (when (buffer-modified-p)
       (save-buffer))
-    (cond ((equal (file-truename old-path)
-                  (file-truename new-path))
+    (cond ((file-equal-p old-path new-path)
            (throw 'status 'overwrite-self))
           ((and (file-exists-p new-path)
                 (not force-p)