Don't make duplicate call to ScenePresence.Close() separately in ETM.DoTeleport() if an agent needs closing.

This is always done as part of Scene.RemoveClient()
Also refactors try/catching in Scene.RemoveClient() to log NREs instead of silently discarding, since these are useful symptoms of problems.

OpenSim/Region/CoreModules/Framework/EntityTransfer/EntityTransferModule.cs

@@ -644,7 +644,6 @@ namespace OpenSim.Region.CoreModules.Framework.EntityTransfer
                 // an agent cannot teleport back to this region if it has teleported away.
                 Thread.Sleep(2000);
 
-                sp.Close();
                 sp.Scene.IncomingCloseAgent(sp.UUID);
             }
             else