We can eliminate the OSD creation code for Ceph < v15.2.0 because Nautilus(v14.2.z)
is no longer supported. In other words, we can now expect that all newly-created
OSDs on PVC are raw mode.
Please note that the existing lvm mode OSDs on PVCs still be supported after this change.
Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>