Bug fix on POST asset so that the new asset service connector can talk to the old asset server.

OpenSim/Framework/Servers/HttpServer/SynchronousRestObjectRequester.cs

@@ -89,11 +89,14 @@ namespace OpenSim.Framework.Servers.HttpServer
             try
             {
                 using (WebResponse resp = request.GetResponse())
+                {
+                    if (resp.ContentLength > 0)
                     {
                         XmlSerializer deserializer = new XmlSerializer(typeof(TResponse));
                         deserial = (TResponse)deserializer.Deserialize(resp.GetResponseStream());
                     }
                 }
+            }
             catch (System.InvalidOperationException)
             {
                 // This is what happens when there is invalid XML