Updates the enable status of delete and reset buttons.

def update_buttons(self):
        """Updates the enable status of delete and reset buttons."""
        current_scheme = self.current_scheme
        names = self.get_option("names")
        try:
            names.pop(names.index(u'Custom'))
        except ValueError:
            pass
        delete_enabled = current_scheme not in names
        self.delete_button.setEnabled(delete_enabled)
        self.reset_button.setEnabled(not delete_enabled)