On 'DELETE' method, convert data to query string path

[rockmkd]

On RFC-7231(https://tools.ietf.org/html/rfc7231#section-4.3.5)

A payload within a DELETE request message has no defined semantics;
sending a payload body on a DELETE request might cause some existing
implementations to reject the request.

So I think DELETE method should use query string rather than message body

CC. @yeonhoyoon