orangefs: report attributes_mask and attributes for statx

OrangeFS formerly failed to set attributes_mask with the result that
software could not see immutable and append flags present in the
filesystem.

Reported-by: Becky Ligon <ligon@clemson.edu>
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Fixes: 68a24a6c ("orangefs: implement statx")
Cc: stable@vger.kernel.org
Cc: hubcap@omnibond.com
Signed-off-by: Mike Marshall <hubcap@omnibond.com>