Initial fix to allow command to proceed without throwing exception.
This is for #2465 - we now get the video duration from `get_video_cache()`.  The `youtube_id` defaults to `video_id` if not found on the video dict.
Merge pull request #2483 from mrpau/hotfix/2465-keyerror-exception-on-generaterealdata-command

Hotfix/2465 keyerror exception on generaterealdata command