qtsound: remove unneeded variable
qtsound: remove unneeded variable

(cherry picked from commit 893716e8371827090a14e5a7257ceeb49f9c0933)

jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2