bug#12170: save-excursion fails boundary case with recenter

[Eli Zaretskii]

> From: "Bill Brodie" <wbrodie@panix.com>
> Date: Fri, 10 Aug 2012 09:40:24 -0400
> Cc: 12170@debbugs.gnu.org
> 
> (1) By "window height", I meant the number of lines displayed for the actual
> buffer, not counting the mode line or minibuffer.  It turns out this is one
> less than the value returned by `window-height'.

As documented, window-height returns the height of the window
including the mode line (and the header line, if there is any).  So
the above is expected.