OGRDataSource: Fix memleaks and use after free in error code path (Coverity 1074121, 1074347, 1074349)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26433 f0d54148-0727-0410-94bb-9a71ac55c965
Fix mem leaks in GDALServerLoop() (Coverity 1074373 and 1074374)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26434 f0d54148-0727-0410-94bb-9a71ac55c965