fix failure to fallthrough to flash when source types included codecs:
fix failure to fallthrough to flash when source types included codecs:

`<source src="pr6.mp4" type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"'>` 

libeo/Vibeo,libeo/Vibeo,libeo/Vibeo,libeo/Vibeo