fix IClientIPEndpoint broken by justin long ago.. but stop using it

except on SceneBanner, later it my be also removed from there and
 everywhere

OpenSim/Framework/Client/IClientIPEndpoint.cs

@@ -34,6 +34,6 @@ namespace OpenSim.Framework.Client
 {
     public interface IClientIPEndpoint
     {
-        IPAddress EndPoint { get; }
+        IPEndPoint  RemoteEndPoint { get; }
     }
 }