Fix what apepars to be a bug in DoubleQueue<T>.Enqueue(Queue<T> q, T data) where the q parmater is ignored and everyghig is always placed on m_lowQueue.

No actual impact presently since nothing ends up calling EnqueueHigh()

OpenSim/Framework/Util.cs

@@ -2253,7 +2253,7 @@ namespace OpenSim.Framework
         {
             lock (m_syncRoot)
             {
-                m_lowQueue.Enqueue(data);
+                q.Enqueue(data);
                 m_s.WaitOne(0);
                 m_s.Release();
             }