Revert "org.el (org-file-contents): Make the message more prominent"

This reverts commit 591d377e7855e6ee36fd9d8c78e262e9a57305df.

lisp/org.el

@@ -5145,10 +5145,9 @@ Support for group tags is controlled by the option
   "Return the contents of FILE, as a string."
   (if (or (not file)
 	  (not (file-readable-p file)))
-      (if (not noerror)
-	  (error "Cannot read file \"%s\"" file)
-	(message "Cannot read file \"%s\"" file)
-	(sit-for 3))
+      (if noerror
+	  (message "Cannot read file \"%s\"" file)
+	(error "Cannot read file \"%s\"" file))
     (with-temp-buffer
       (insert-file-contents file)
       (buffer-string))))