message: Amend error response to indicate that we return additional error info.
diff: "description": "Error message indicating why the operation failed.",
  "type": "string",
  "readOnly": true
  + },
  + "additionalInfo": {
  + "readOnly": true,
  + "type": "array",
  + "items": {
  + "$ref": "#/definitions/ErrorAdditionalInfo"
  + },
  + "description": "The error additional info."
  }
  }
  },
  }
  }
  },
  + "ErrorAdditionalInfo": {
  + "properties": {
  + "type": {
  + "readOnly": true,
  + "type": "string",
  + "description": "The additional info type."
  + },
  + "info": {
  + "readOnly": true,
  + "type": "object",
  + "description": "The additional info."
  + }
  + },
  + "description": "The resource management error additional info."
  + },
  "Resource": {
  "description": "An Azure resource.",
  "required": [
  