orangefs: react properly to posix_acl_update_mode's aftermath.

posix_acl_update_mode checks to see if the permissions
described by the ACL can be encoded into the
object's mode. If so, it sets "acl" to NULL
and "mode" to the new desired value. Prior to this patch
we failed to actually propagate the new mode back to the
server.

Signed-off-by: Mike Marshall <hubcap@omnibond.com>