matroskademux: consider TrackUID==0 a warning and not handle it as error
Fixes: #1821 (closed)
some special files whose trackUID is 0 can be played on the other player. But it cannot be played in gstreamer,because trackUID 0 will be treated as an error in matroskademux.
So, it makes sense to only consider trackUID==0 a warning and not handle it as error
Edited by Yu Shengqi