This may have led to spurious "IO Errors" on a receiving node, when
barriers are not disabled, and not supported by the lower level device.

regression was introduced by:
commit a2ad6507a0b5a2dc1f5a6a823b9a28d9c4430200
Author: Lars Ellenberg <lars.ellenberg@linbit.com>
Date:   Thu Aug 27 20:40:39 2009 +0200

    fix potential endless retry loop on IO error
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>