ogr_vfk: fix VFK DB name

git-svn-id: https://svn.osgeo.org/gdal/trunk@27651 f0d54148-0727-0410-94bb-9a71ac55c965
VFK: fix segfault introduced in r27648


git-svn-id: https://svn.osgeo.org/gdal/trunk@27652 f0d54148-0727-0410-94bb-9a71ac55c965