XYZ: fix back line seeking with datasets that have not the same number of values per lines (#5488)

git-svn-id: https://svn.osgeo.org/gdal/trunk@27401 f0d54148-0727-0410-94bb-9a71ac55c965
GDAL applications: only list raster capable drivers in error messages

git-svn-id: https://svn.osgeo.org/gdal/trunk@27403 f0d54148-0727-0410-94bb-9a71ac55c965