rbd: replace go-ceph GetParentInfo() with GetParent()
rbd: replace go-ceph GetParentInfo() with GetParent()

GetParent() is a newer and better version of
GetParentInfo() in go-ceph.

Signed-off-by: Mudit Agarwal <e5356c34e3b3b8ef2f9750bb431df6fcd5e2fa6e@redhat.com>

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