Description of problem:
When replacing controller-0, current documentation misses to state that the following lines of overcloud-without-mergepy.yaml should be have the index changed from 0 to 1 (or other value representing an existing controller node).

  # All Nodes Validations
  AllNodesValidationConfig:
    type: OS::TripleO::AllNodes::Validation
    properties:
      PingTestIps:
        list_join:
        - ' '
        - - {get_attr: [Controller, resource.0.external_ip_address]}
          - {get_attr: [Controller, resource.0.internal_api_ip_address]}
          - {get_attr: [Controller, resource.0.storage_ip_address]}
          - {get_attr: [Controller, resource.0.storage_mgmt_ip_address]}
          - {get_attr: [Controller, resource.0.tenant_ip_address]}