bug#25179: 26.0.50; Dired doesn't preserve window height

[Tino Calancha]

On Sat, 15 Apr 2017, martin rudalics wrote:

> > emacs -Q
> > C-x 2
> > ;; Visit a directory with several hundred of files.
> > M-: (dired (expand-file-name "lisp" source-directory))
> > RET
> > t D no RET
> > ;; In both releases the window displaying *scratch* becames very small.
>
> This should not happen any more after my last commit.  Please check.
Checked it.  It's OK now.  Thank you.