rbd: make setThickProvisioned as method of rbdImage
rbd: make setThickProvisioned as method of rbdImage

isThickProvisioned is already method of the rbdImage
to keep similar thick provisioner related functions
common making isThickProvisioned as method of rbdImage.

Signed-off-by: Madhu Rajanna <60fbf37a92c2a0908e31296d18dadbec5a4dae17@gmail.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi