remove the video from the toy course for now as the import-export-import isn't totally equivalence.

common/test/data/toy/vertical/vertical_test.xml

 <sequential>
-        <video display_name="default" youtube_id_0_75="JMD_ifUUfsU" youtube_id_1_0="OEoXaMPEzfM" youtube_id_1_25="AKqURZnYqpk" youtube_id_1_5="DYpADpL7jAY" name="sample_video"/>
         <poll_question name="T1_changemind_poll_foo_2" display_name="Change your answer" reset="false">
         <p>Have you changed your mind?</p>
         <answer id="yes">Yes</answer>