muxer: Fix handling of stream's porperty changes.
muxer: Fix handling of stream's porperty changes.

This regression is introduced at 32ae212 .

maki-rxrz/L-SMASH,maki-rxrz/L-SMASH,l-smash/l-smash,l-smash/l-smash,canbal/l-smash,dwbuiten/l-smash,l-smash/l-smash,canbal/l-smash,dwbuiten/l-smash,silverfilain/L-SMASH,silverfilain/L-SMASH,silverfilain/L-SMASH