Get rid of postgis_drop_before for extension upgrade -- we don't need it any more after #2334

git-svn-id: http://svn.osgeo.org/postgis/trunk@11539 b70326c6-7e19-0410-871a-916f4a2858ee
#2356: quick fix for extensions not building anymore because of raster upgrade file change from rtpostgis_upgrade_20_minor.sql to rtpostgis_upgrade_20_21.sql

Also got rid of some commented out code

git-svn-id: http://svn.osgeo.org/postgis/trunk@11540 b70326c6-7e19-0410-871a-916f4a2858ee