message: Add 404 for get operations in appliance spec
diff: "$ref": "#/definitions/Appliance"
  }
  },
  + "404": {
  + "description": "Not Found"
  + },
  "default": {
  "description": "Error response describing why the operation failed.",
  "schema": {
  "$ref": "#/definitions/ApplianceDefinition"
  }
  },
  + "404": {
  + "description": "Not Found"
  + },
  "default": {
  "description": "Error response describing why the operation failed.",
  "schema": {
  "$ref": "#/definitions/Appliance"
  }
  },
  + "404": {
  + "description": "Not Found"
  + },
  "default": {
  "description": "Error response describing why the operation failed.",
  "schema": {
  "$ref": "#/definitions/ApplianceDefinition"
  }
  },
  + "404": {
  + "description": "Not Found"
  + },
  "default": {
  "description": "Error response describing why the operation failed.",
  "schema": {
  