Regression fix: module article news show old news first

After updating to 3.2.0 module article news show old.
To really fix the issue reported: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=28349&start=0

We should add desc/asc ordering in the menu while the current option should stay desc. Do not change the way it's currently work for backward compatibility.