RPC unit tests for cluster_policy_attach/detach
RPC unit tests for cluster_policy_attach/detach

This patch adds two missing unit tests at RPC client.

Change-Id: I12f5bc9105a87fc4abd1a939d587fb3632c2a7b1

stackforge/senlin,openstack/senlin,stackforge/senlin,tengqm/senlin-container,openstack/senlin,tengqm/senlin-container,openstack/senlin