[ooyala] Try mobile player JS URLs for all available devices (Closes #3498)

Looks like some videos are only available for particular devices
(e.g. http://player.ooyala.com/player.js?embedCode=x1b3lqZDq9y_7kMyC2Op5qo-p077tXD0
is only available for ipad)
Working around with fetching URLs for all the devices found starting with 'unknown'
until we succeed or eventually fail for each device.