Fix typo in Makefile.am

Makefile.am

@@ -120,7 +120,7 @@ csharp_EXTRA_DIST=                                                           \
   csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs                   \
   csharp/src/Google.Protobuf/Reflection/FieldType.cs                         \
   csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs                    \
-  csharp/src/Google.Protobuf/Reflection/GenerateCodeInfo.cs                  \
+  csharp/src/Google.Protobuf/Reflection/GeneratedCodeInfo.cs                 \
   csharp/src/Google.Protobuf/Reflection/IDescriptor.cs                       \
   csharp/src/Google.Protobuf/Reflection/IFieldAccessor.cs                    \
   csharp/src/Google.Protobuf/Reflection/MapFieldAccessor.cs                  \