In XAssetService, on a delete asset request also delete the asset in any chained service.

This eliminates the async migration since it causes a race condition with the "delete asset" console command

OpenSim/Data/MySQL/MySQLXAssetData.cs

@@ -199,6 +199,8 @@ namespace OpenSim.Data.MySQL
         /// <remarks>On failure : Throw an exception and attempt to reconnect to database</remarks>
         public void StoreAsset(AssetBase asset)
         {
+//            m_log.DebugFormat("[XASSETS DB]: Storing asset {0} {1}", asset.Name, asset.ID);
+
             lock (m_dbLock)
             {
                 using (MySqlConnection dbcon = new MySqlConnection(m_connectionString))