Revert "Add comment about setting client.SceneAgent in AddNewClient()"

This reverts commit 964cae4f37.

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -2670,10 +2670,7 @@ namespace OpenSim.Region.Framework.Scenes
                     sp.IsChildAgent ? "child" : "root", sp.Name, RegionInfo.RegionName);
             }
 
-            // We must set this here so that TriggerOnNewClient and TriggerOnClientLogin can determine whether the
-            // client is for a root or child agent.
             client.SceneAgent = sp;
-
             m_LastLogin = Util.EnvironmentTickCount();
 
             // Cache the user's name