Fixes #11061. Speed up TFW recovery after falling behind on writes.

Signed-off-by: Daniel Thor Kristjansson <danielk@cuymedia.net>
(cherry picked from commit dc0bf9b03248775bbd186f4029b217bba9d4b6a6)
DTVRecorder::ResetForNewFile: Don't reset possibly needed stream information
when switching ringbuffers.
Merge branch 'stable' of github.com:sivchandk/mythtv-stabilize into stable