According to the official HTTP/1.1 specs a successful DELETE request
can be handled in various ways.

> If a DELETE method is successfully applied, the origin server SHOULD send a 202 (Accepted) status code if the action will likely succeed but has not yet been enacted, a 204 (No Content) status code if the action has been enacted and no further information is to be supplied, or a 200 (OK) status code if the action has been enacted and the response message includes a representation describing the status.

This commit will make sure a 204 HTTP status code is returned
after successfully cancelling the session.

…nse code.

…IRMA session.