THRIFT-209. csharp: Make TTransportFactory.GetTransport virtual


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@739641 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/csharp/src/Transport/TTransportFactory.cs b/lib/csharp/src/Transport/TTransportFactory.cs
index 1cb5c92..a0a6c2b 100644
--- a/lib/csharp/src/Transport/TTransportFactory.cs
+++ b/lib/csharp/src/Transport/TTransportFactory.cs
@@ -24,7 +24,7 @@
 	/// </summary>
 	public class TTransportFactory
 	{
-		public TTransport GetTransport(TTransport trans)
+		public virtual TTransport GetTransport(TTransport trans)
 		{
 			return trans;
 		}