Fix EME 01b multi-session bug
Created by: greg80303
Queue up pending sessions until we receive the associated key message
When multiple keys are requested initially, the createKeySession calls in before the first keymessage is generated. This means that we can't detect whether or not multiple key sessions are supported until after multiple key sessions have already been created. This is something that we can't avoid with this early EME API version.
The outcome is that if you try to play encrypted content that uses more than one key on a user agent that implements the 01b API and DOES NOT support sessionIDs, you will get unpredictable results.
At this point, I do not know of any browsers that will cause this error, so I just log an error message