Don't call libmegapixels_open twice in a row in io_pipeline

src/io_pipeline.c

@@ -577,7 +577,6 @@ update_state(MPPipeline *pipeline, const mp_state_io *new_state)
 
                 state_io.camera = new_state->camera;
                 if (state_io.camera) {
-                        libmegapixels_open(state_io.camera);
                         mpcamera = mp_camera_new(state_io.camera);
                         state_io.mode_preview = NULL;
                         state_io.mode_capture = NULL;