[mythtv] livetv seeking bug

[Mark Weaver]

> My guess would be DecoderBase::SyncPositionMap(), which copies
> portions of the position map from the backend to the frontend.
> I believe this tries to only copy the new portions of the position
> map, and there may be some problems with how position map resets
> are handled.
> 
> But it could also be a problem with the position map itself, in
> which case DTVRecorder::HandleKeyframe(void) or TVRec could be
> the problem. I think this less likely.
> 
I can only get this to happen with the DVB card.  The PVR-150 I have 
works fine.

I'll try and figure out what the code does now!