Upstream /sys/bus/rbd/supported_features is part of Linux kernel v4.11.0
Prepare the attributes and use them in case if
/sys/bus/rbd/supported_features is missing.
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
(cherry picked from commit e53fd8715422dc436d61e1fae09c8370aaa650ce)