#2279: fix inability to upgrade from 2.0 to 2.1 by renaming old geog/geom selectivity functions to new name (if they are currently used) aand then allowing the standard upgrade to steam roll over the definitions.

git-svn-id: http://svn.osgeo.org/postgis/trunk@11327 b70326c6-7e19-0410-871a-916f4a2858ee