Pass the "attachToBackup" bool given to SceneGraph.AddNewSceneObject() down into the 3-parameter AddNewSceneObject() method instead of always hardcoding true.

This doesn't affect any core OpenSimulator code since all callers were passing true anyway
But it allows region modules to create objects that are never persisted.

OpenSim/Region/Framework/Scenes/SceneGraph.cs

@@ -300,7 +300,7 @@ namespace OpenSim.Region.Framework.Scenes
         public bool AddNewSceneObject(
             SceneObjectGroup sceneObject, bool attachToBackup, Vector3? pos, Quaternion? rot, Vector3 vel)
         {
-            AddNewSceneObject(sceneObject, true, false);
+            AddNewSceneObject(sceneObject, attachToBackup, false);
 
             if (pos != null)
                 sceneObject.AbsolutePosition = (Vector3)pos;