rbd: allocate extents when expanding an image
rbd: allocate extents when expanding an image

When and RBD image is expanded, the additional extents need to get
allocated when the image was thick-provisioned.

Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>

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