message: qt: Add cancel button to configuration options popup
  This adds a cancel buttion to the configuration options window
diff: @@ -287,11 +287,23 @@ void OptionsDialog::on_resetButton_clicked()
  void OptionsDialog::on_openBitcoinConfButton_clicked()
  {
  - /* explain the purpose of the config file */
  - QMessageBox::information(this, tr("Configuration options"),
  - tr("The configuration file is used to specify advanced user options which override GUI settings. "
  + QMessageBox config_msgbox(this);
  + config_msgbox.setIcon(QMessageBox::Information);
  + //: Window title text of pop-up box that allows opening up of configuration file.
  + config_msgbox.setWindowTitle(tr("Configuration options"));
  + /*: Explanatory text about the priority order of instructions considered by client.
  + The order from high to low being: command-line, configuration file, GUI settings. */
  + config_msgbox.setText(tr("The configuration file is used to specify advanced user options which override GUI settings. "
  "Additionally, any command-line options will override this configuration file."));
  + QPushButton* open_button = config_msgbox.addButton(tr("Continue"), QMessageBox::ActionRole);
  + config_msgbox.addButton(tr("Cancel"), QMessageBox::RejectRole);
  + open_button->setDefault(true);
  +
  + config_msgbox.exec();
  +
  + if (config_msgbox.clickedButton() != open_button) return;
  +
  /* show an error if there was some problem opening the file */
  if (!GUIUtil::openBitcoinConf())
  QMessageBox::critical(this, tr("Error"), tr("The configuration file could not be opened."));
  