Cycles: fix some update issues with camera motion blur, and do some more work

for getting object motion blur ready.

intern/cycles/blender/blender_sync.cpp

@@ -17,6 +17,7 @@
  */
 
 #include "background.h"
+#include "camera.h"
 #include "film.h"
 #include "../render/filter.h"
 #include "graph.h"
@@ -179,6 +180,11 @@ void BlenderSync::sync_integrator()
 
 	integrator->sample_clamp = get_float(cscene, "sample_clamp");
 #ifdef __CAMERA_MOTION__
+	if(integrator->motion_blur != r.use_motion_blur()) {
+		scene->object_manager->tag_update(scene);
+		scene->camera->tag_update();
+	}
+
 	integrator->motion_blur = (!preview && r.use_motion_blur());
 #endif