Change the index of this source handler

[benvirus]

This source handler should not be place at the 0 index since the videojs has H5 native handler. We should judge if the native handler can handle the source firstly.

[mrbar42]

@benvirus thanks for the PR

could you give some background for this change

[benvirus]

@mrbar42 If set this handler at 0 index, when the Html5 tech instance invoke the selectSourceHandler method, this source handler will be judged before the native source handler of Html5. It should be better to judge native source handler firstly since we should use the native handler if it is support the source which was offered. Request For Comment.