fix mixer crash on disconnect
fix mixer crash on disconnect


SVN revision: 80590

FlorentRevest/Enlightenment,tizenorg/platform.upstream.enlightenment,tasn/enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,rvandegrift/e,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,tasn/enlightenment