The current code in xlog_iodone() uses the wrong macro to check if the
barrier has been cleared due to an EOPNOTSUPP error form the lower layer.

SGI-PV: 986143

SGI-Modid: xfs-linux-melb:xfs-kern:31984a
Signed-off-by: NDavid Chinner <david@fromorbit.com>
Signed-off-by: NNathaniel W. Turner <nate@houseofnate.net>
Signed-off-by: NPeter Leckie <pleckie@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>