fix interop_matrix C# tests for v1.1.4
diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index 4345031..35e4554 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -98,7 +98,7 @@
     ],
    'csharp': [
         #'v1.0.1',
-        #'v1.1.4',  Fail to build.
+        'v1.1.4',
         'v1.2.5',
         'v1.3.9',
         'v1.4.2',