VFK: remove unused variable (cosmetics)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@27649 f0d54148-0727-0410-94bb-9a71ac55c965
VFK: add missing doxygen docs for IVFKDataBlock::GetFeatureCount()

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@27650 f0d54148-0727-0410-94bb-9a71ac55c965