Clang: Remove unused RefactoringServerProxy::ioDevice

Change-Id: Ie2cb946750ada2f89aa329499f9daaded48ba88e
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/clangbackendipc/refactoringserverproxy.h

@@ -60,7 +60,6 @@ private:
     ClangBackEnd::WriteMessageBlock writeMessageBlock;
     ClangBackEnd::ReadMessageBlock readMessageBlock;
     RefactoringClientInterface *client = nullptr;
-    QIODevice *ioDevice = nullptr;
 };
 
 } // namespace ClangBackEnd