edx/edx-platform — pull request #296 by valera-rozuvan (2013-06-28 09:35:52+00:00)
Title: Valera/bugfix allow no youtube attribute

Original problem (including description from https://edx-wiki.atlassian.net/browse/BLD-152 ):
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If I remove the youtube attribute of the videoalpha player, I get an error from youtube rather than failing over to the other videos that I have provided.

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The fix is basically making sure that either an empty string is passed or a correctly formated string of YouTube IDs.

@rocha Please review.