Delete the ca-rotate api-ref

'ca-rotate' hasn't been supported, 'ERROR: 'rotate_ca_certificate'
is not supported by this driver (HTTP 400)' will be returned.
So, I think we should supply the api after it's realization.

Change-Id: I698b9df3876dd9fa4e1685973762d92ec3a5f7ca

api-ref/source/certificates.inc

@@ -119,29 +119,3 @@ Response Example
 
 .. literalinclude:: samples/certificates-ca-sign-resp.json
    :language: javascript
-
-Rotate the CA certificate for a bay/cluster
-===========================================
-
-.. rest_method:: PATCH /v1/certificates/{bay_uuid/cluster_uuid}
-
-Rotate the CA certificate for a bay/cluster and invalidate all user
-certificates.
-
-Response Codes
---------------
-
-.. rest_status_code:: success status.yaml
-
-   - 202
-
-.. rest_status_code:: error status.yaml
-
-   - 400
-
-Request
--------
-
-.. rest_parameters:: parameters.yaml
-
-   - cluster: cluster_id