hlsdemux: Update all live variant/rendition streams
Submitted by Seungha Yang
Updating manifest triggers live playback timeline update
(i.e., setting "first_file_start" and "last_file_end" of a m3u8).
However, deactivated variant/rendition streams never be updated,
and it causes timeline mismatch between them.
To keep track of timeline of each streams, demux needs to update all of them.