#2704, ST_DumpPoints of EMPTY geometries crashes server


git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@12431 b70326c6-7e19-0410-871a-916f4a2858ee
Fix ticket #


git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@12433 b70326c6-7e19-0410-871a-916f4a2858ee