message: Fix issue in JSONAPISource#fetch error handling
  There was an issue in JSONAPISource#fetch that caused an extra
  JSONAPISource#handleFetchResponse function call with a null argument, when
  there is a timeout and the Orbit#fetch call rejects.
diff: @@ -182,20 +182,17 @@ export default class JSONAPISource extends Source implements Pullable, Pushable
  Orbit.globals.clearTimeout(timer);
  if (!timedOut) {
  - return this.handleFetchError(e)
  - .then(response => resolve(response))
  - .catch(e => reject(e));
  + return this.handleFetchError(e);
  }
  })
  .then(response => {
  Orbit.globals.clearTimeout(timer);
  if (!timedOut) {
  - return this.handleFetchResponse(response)
  - .then(response => resolve(response))
  - .catch(e => reject(e));
  + return this.handleFetchResponse(response);
  }
  - });
  + })
  + .then(resolve, reject);
  });
  } else {
  return Orbit.fetch(url, settings)
  