Make postgis_proc_upgrade ready to deal with rtpostgis.sql

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@12241 b70326c6-7e19-0410-871a-916f4a2858ee
Generate raster upgrade script using postgis_proc_upgrade

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@12242 b70326c6-7e19-0410-871a-916f4a2858ee