dired-do-copy messages vs. slow devices

[Dan Jacobson]

Let's discuss what happens when one uses dired-do-copy
and answers "y" to e.g.,
  Overwrite `/var/tmp/smaller2.cpio'? [Type yn!q or C-h]

Well, in the case of slow devices and big files, that message will
stay there for a long time while the copy is taking place.

Therefore perhaps add some dots or something showing at least that
emacs got our answer and is acting on it and is not still asking us.