OGR SQL: fix SELECT * on a layer with a field that has a dot character (#5379)

git-svn-id: https://svn.osgeo.org/gdal/trunk@26930 f0d54148-0727-0410-94bb-9a71ac55c965
Fix possible null pointer dereference

git-svn-id: https://svn.osgeo.org/gdal/trunk@26931 f0d54148-0727-0410-94bb-9a71ac55c965