Fixed two types of tests for box
Fixed two types of tests for box

- In aiohttp3, Client Response's json() method requires the content
  type header. The default expectation is application/json. Thus,
  `'headers': {'Content-Type': 'application/json'}` must be provided
  during URI registration (if `.json()` is called by the response).
- After the initial upgrade, core provider's make_request() now uses
  upper case for HTTP method. All lower case methods must be changed
  during URI registration in tests.

CenterForOpenScience/waterbutler,felliott/waterbutler