Fix YouTube assets on demo app.
Fix YouTube assets on demo app.

The YouTube test assets use an embedded URL for the license server.
This URL may actually be http.  This is rejected when using the demo
app over https due to mixed content restrictions in the browser.

Issue #682

Change-Id: Ib7533f7174f4abe25a8810f9b7a9548130ea2876

TobbeEdgeware/shaka-player,brightcove/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,vimond/shaka-player,brightcove/shaka-player,shaka-project/shaka-player,russitto/shaka-player,tvoli/shaka-player,indiereign/shaka-player,shaka-project/shaka-player,TobbeEdgeware/shaka-player,tvoli/shaka-player,Ross-cz/shaka-player,tvoli/shaka-player,vimond/shaka-player,TheModMaker/shaka-player,tvoli/shaka-player,indiereign/shaka-player,russitto/shaka-player,brightcove/shaka-player,Ross-cz/shaka-player,indiereign/shaka-player,TheModMaker/shaka-player,russitto/shaka-player,vimond/shaka-player,TobbeEdgeware/shaka-player,Ross-cz/shaka-player