Use request.fullpath to check whether to save URL

Match against request.fullpath instead of controller_path when
determining whether or not to save a previous URL.
Switch to RSpec expect syntax
Call perform_http_request in Cucumber steps

- Call WebpageService.perform_http_request in Cucumber step definitions
  for URLs that have already been submitted
- Set perform_http_request transient attribute for webpage_request
  factory to true in WebpagesController spec