Fixed std::atomic_flag initialization.

src/stereo_camera.hpp

@@ -107,7 +107,7 @@ struct stereo_camera {
 private:
 
     std::thread *trigger_thread = nullptr;
-    std::atomic_flag should_stop = false;
+    std::atomic_flag should_stop;
 
     bool open_impl() {
         CALL_CHECK(left_camera.open(left_camera_name));