GXFOpen let the file opened when fails

[dem@…]

in gdal/frmts/gxf/gxfopen.c

if GXFOpen fails the function returns directly without close the opened file in
binary mode "fp" :

/* -------------------------------------------------------------------- */
/*      Did we find the #GRID?                                          */
/* -------------------------------------------------------------------- */
    if( !EQUALN(szTitle,"#GRID",5) )
    {
        CPLError( CE_Failure, CPLE_WrongFormat,
                  "Didn't parse through to #GRID successfully in.\n"
                  "file `%s'.\n",
                  pszFilename );
        
        return NULL;
    }

Maybe just add a GXFClose before the return solve the problem...

Julien

[warmerdam]

Problem and fix confirmed and applied.