org.el (org-overview): Stay on current line

org.el (org-overview): Stay on current line

* org.el (org-overview): Stay on current line.

This circumvents a bug in hide-sublevels which displays the
"..." ellipsis on top of the window when hiding levels that
are past the middle of the window---at least this is the
way I could understand the problem.

Thanks to Samuel Wales for reporting the problem, Arun Persaud and
William for creating reproducible recipes, Suvayu Ali, Nick Dokos
and Achim Gratz for further help.