no error is raised if you try to PUT/POST data without the proper content type

This change fixes an issue where you could `POST` or `PUT` data to an end point without setting the content type first.  While working with the API to create a job type I forgot to set the content type prior to sending the request which caused the endpoint's code to throw an internal server error rather than a more useful error code telling me what was wrong.  As a result of incorrectly processing the content type `g.json` was not set up prior to entering into the endpoint causing the exception to be raised.