Fix bug with only caching rendered article content
Fix bug with only caching rendered article content

- Previously we were only caching guides with their rendered text to save on
  cache space.  However, we changed this in aef16ae23.  We now do all the
  markdown rendering on the front-end because it saves an extra github API
  request.  Unfortunately, we never changed our caching strategy to cache
  guides if we didn't render their content first.

pluralsight/guides-cms,pluralsight/guides-cms,pluralsight/guides-cms