ceph: update Kubernetes registry link in CephFS document
ceph: update Kubernetes registry link in CephFS document

Update Kubernetes link to version 1.9.X which includes registry addon.

Ref:
https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.10.md
https://github.com/kubernetes/kubernetes/pull/58564

Signed-off-by: chienfuchen32 <fb58279631ccd2a55728e75accf64f8388175899@gmail.com>

rook/rook,rook/rook,rook/nfs,rook/rook,rook/nfs,rook/nfs,rook/rook,rook/rook