[mythtv] 0.21 and ffmpeg handling of corrupt ac3

[Anduin Withers]

> It occurred to me that, if at any point mythtv uses a newer version of
> ffmpeg, this issue will pretty much fix itself.  In any case, if
> anyone thinks I should log a bug, and maybe post my patch for anyone
> looking for a quick fix, let me know.  I already posted it to the
> users list.

A new ffmpeg sync will happen at some point, don't let that stop you from
opening a ticket (if for no other reason than a reminder to do something in
0.21-fixes).

--
Anduin Withers