KEA: replace atof() by CPLAtof()

git-svn-id: https://svn.osgeo.org/gdal/trunk@28014 f0d54148-0727-0410-94bb-9a71ac55c965
Improve KEA RAT testing



git-svn-id: https://svn.osgeo.org/gdal/trunk@28015 f0d54148-0727-0410-94bb-9a71ac55c965