The Content-Type header for a request "Accept:application/vnd.swagger+json" seems to be wrong

I tried to request the following API:
```bash
http GET http://localhost:8888/apigility/documentation/Test/User 'Accept:application/vnd.swagger+json'
```
where Test is the API name and User is a RESTful service name, and I obtained the following output:
```bash
HTTP/1.1 200 OK
Connection: close
Content-Type: application/json; charset=utf-8
```
The output is a valid Swagger format but the Content-Type is JSON and not application/vnd.swagger+json.