Getting _settings or _mapping for non-existing index returns 200 OK

[karmi]

When doing a request for index settings or mapping, when the index does not exist, ES returns a 200 OK response:

$ curl -i localhost:9200/NOTEXISTING/_mapping
HTTP/1.1 200 OK
Content-Type: application/json; charset=UTF-8
Content-Length: 2

{}

$ curl -i localhost:9200/NOTEXISTING/_settings
HTTP/1.1 200 OK
Content-Type: application/json; charset=UTF-8
Content-Length: 2

{}

It should return an error response, such as 404 Not Found.