OGR PDS: fix potential use after free (Coverity 1074119)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26435 f0d54148-0727-0410-94bb-9a71ac55c965
Use correct sizeof() (Coverity 1074535)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26436 f0d54148-0727-0410-94bb-9a71ac55c965