Remove unnecessary get_status_code wrapper function

Function get_status_code is used to get HTTP status code from
either requests.Response (status_code) or Webob.Response
(status_int). The latter was removed in 2012 and not needed
anymore.

Change-Id: Iacd6bbb83ce0d8ec5b8ec73273bc7bf39c9ccc8d
Merge "Remove unnecessary get_status_code wrapper function"