Valgrind reports a memory leak in QApplication::clipboard()->setText();

Valgrind reports leak in `QApplication::clipboard()->setText("text");` call when closing application.

A sample project attached.

To reproduce:
1. Run the project with Valgrind.
2. Make sure you don't have anything important in the clipboard.
3. Push the button.
4. Close application's window.
5. See Valgrind's output.

The output I get is also attached.