KaxSemantic.cpp: remove the default value of some new TrackEntry elements
KaxSemantic.cpp: remove the default value of some new TrackEntry elements

See https://github.com/ietf-wg-cellar/matroska-specification/commit/4dbdf03f04798584085b34236a750681c7d4a1a5

Matroska-Org/libmatroska,Matroska-Org/libmatroska,Matroska-Org/libmatroska