THRIFT-2050 Vagrant C# lib compile fails with TException missing

Patch: Justin Porterfield
diff --git a/lib/csharp/Makefile.am b/lib/csharp/Makefile.am
index 7bc161d..71cc83b 100644
--- a/lib/csharp/Makefile.am
+++ b/lib/csharp/Makefile.am
@@ -59,6 +59,7 @@
             src/Transport/THttpHandler.cs \
             src/Transport/TMemoryBuffer.cs \
             src/TProcessor.cs \
+            src/TException.cs \
             src/TApplicationException.cs
 
 CSC=gmcs