Pause state confusion when changing source

[John Veness <John.Veness.mythtv@…>]

Steps to reproduce:

1, Go into Watch Recordings
2, Start playback of any recording
3, Pause playback
4, Go into menu
5, Choose Source, Jump to Program, Recorded Program, and pick another recording
6, The chosen recording starts playing

At this point, although the chosen recording seems to be playing back OK, things aren't quite right. If you press "I" on the keyboard, there is no response (should be a progress bar). If you use the left or right cursor keys, instead of skipping by 30 or 5 seconds, only one frame (guessing) is skipped in either direction. If you press "P", instead of pausing, the OSD says "Play" and playback continues (a second press of "P" will pause).

I haven't looked at the code, but I think what is happening is that, despite the recording playing back, something "thinks" it is paused, which is why the "I" key has no response (as it doesn't when paused), why the press of "P" makes it think that it needs to start playing, and why the left and right cursor keys only skip one frame.