ILI: fix segfault caused by previous commit

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@27187 f0d54148-0727-0410-94bb-9a71ac55c965
GML: fix crash when setting the geometry of index > 0 when none has been set until now (trunk only)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@27188 f0d54148-0727-0410-94bb-9a71ac55c965