requestBody reference ignored

[jschaeff]

When I describe an operation like this:

 operation :query_post,
    request_body:  %Reference{"$ref": "#/components/requestBodies/query"}

the request body ref is silently ignored, it does not appear in the /openapi json description.

On the contrary, putting directly the requestBody struct works:

 operation :query_post,
    request_body:  %RequestBody{description: "the body"}