fix for bug 169039. GFS no longer checks permissions before truncating a
    file in gfs_setattr.  I don't know what this check was ever added (It didn't
    exist in gfs 6.0). Since I don't know why the check was added, I can't say
    for certain that it is unessential.  However, I can't see any reason to do
    it, so I commented it out.