API config block used?

#### Version information:
```
$ ipfs version --all
go-ipfs version: 0.4.18-
Repo version: 7
System version: amd64/linux
Golang version: go1.11.1
```

#### Type:
Bug?

#### Description:
Does the API service still use the API config block? As you can see from below, I have two headers set and one is not in the response and the other has a different value. This seems to suggest that this config block is no longer utilized?

Allow headers and expose headers is set on the gateway config as well but are returned in a response to the API. So headers that should be present are not and headers that shouldn't be present are?

```
$ curl -I "http://127.0.0.1:5001/api/v0/refs?r=true&arg=QmRycVjyfDFtVo28sKjSVwDqXiuPiXw6XGmGrB6NJYWSW9"
HTTP/1.1 200 OK
Access-Control-Allow-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
Access-Control-Expose-Headers: X-Stream-Output, X-Chunked-Output, X-Content-Length
Content-Type: application/json
Server: go-ipfs/0.4.18
Trailer: X-Stream-Error
Vary: Origin
X-Chunked-Output: 1
Date: Sun, 23 Dec 2018 17:43:35 GMT

$ ipfs config API
{
"HTTPHeaders": {
"Access-Control-Allow-Origin": [
"*"
],
"Server": [
"go-ipfs/0.4.17"
]
}
}
```