MythPlayer: Reorder pause/unpause sequence.

The pause/unpause behaviour will be highly dependant on which thread is
calling Pause(), but broadly speaking the most involved and hence time
critical action is pausing/unpausing the decoder. Hence do this last on
pause so that the video (i.e. main thread) is more responsive and
unpause the decoder first before the video thread is occupied.
(cherry picked from commit b4f1039)

mythtv/libs/libmythtv/mythplayer.cpp

@@ -337,9 +337,9 @@ bool MythPlayer::Pause(void)
     }
     next_play_speed   = 0.0;
     next_normal_speed = false;
-    PauseDecoder();
     PauseVideo();
     audio.Pause(true);
+    PauseDecoder();
     PauseBuffer();
     allpaused = decoderPaused && videoPaused && bufferPaused;
     {
@@ -368,10 +368,10 @@ bool MythPlayer::Play(float speed, bool normal, bool unpauseaudio)
     }
 
     UnpauseBuffer();
+    UnpauseDecoder();
     if (unpauseaudio)
         audio.Pause(false);
     UnpauseVideo();
-    UnpauseDecoder();
     allpaused = false;
     next_play_speed   = speed;
     next_normal_speed = normal;