fix crash when disc_init() fails
fix crash when disc_init() fails

Not likely, but possible (failed malloc would cause this).

koying/libbluray,tourettes/libbluray,vlc-mirror/libbluray,tourettes/libbluray,vlc-mirror/libbluray,ShiftMediaProject/libbluray,ShiftMediaProject/libbluray,Azzuro/libbluray,mwgoldsmith/bluray,mwgoldsmith/bluray,koying/libbluray,EdwardNewK/libbluray,EdwardNewK/libbluray,vlc-mirror/libbluray,tourettes/libbluray,Distrotech/libbluray,koying/libbluray,ace20022/libbluray,EdwardNewK/libbluray,vlc-mirror/libbluray,ace20022/libbluray,EdwardNewK/libbluray,Azzuro/libbluray,ShiftMediaProject/libbluray,ShiftMediaProject/libbluray,Distrotech/libbluray,ace20022/libbluray,tourettes/libbluray,Distrotech/libbluray,mwgoldsmith/bluray,Azzuro/libbluray,Distrotech/libbluray,ace20022/libbluray,mwgoldsmith/bluray,koying/libbluray,Azzuro/libbluray