respect landpoint Z position also on the ugly LandingPointBehavior_OS option (default one)

OpenSim/Region/Framework/Scenes/ScenePresence.cs

@@ -5947,6 +5947,7 @@ namespace OpenSim.Region.Framework.Scenes
                          (m_teleportFlags & Constants.TeleportFlags.ViaHGLogin) != 0))
                     {
                         pos = land.LandData.UserLocation;
+                        positionChanged = true;
                     }
                 }