test: delete mpeg2lg buffer to fix mem leak
test: delete mpeg2lg buffer to fix mem leak

Issue reported by Kai Huettemann.

xunchangguo/BMX,xunchangguo/BMX,Limecraft/ebu-bmx,Limecraft/ebu-bmx,Limecraft/ebu-bmx,stuarthicks/bmx,kierank/bmxlib-bmx,xunchangguo/BMX,kierank/bmxlib-bmx,stuarthicks/bmx,stuarthicks/bmx,kierank/bmxlib-bmx