gui: Apply port mapping changes on dialog exit

This commit does not change behavior. It is a prerequisite for NAT-PMP
support adding.

src/qt/optionsdialog.cpp

@@ -24,6 +24,7 @@
 #include <QIntValidator>
 #include <QLocale>
 #include <QMessageBox>
+#include <QSettings>
 #include <QSystemTrayIcon>
 #include <QTimer>
 
@@ -50,6 +51,10 @@ OptionsDialog::OptionsDialog(QWidget *parent, bool enableWallet) :
 #ifndef USE_UPNP
     ui->mapPortUpnp->setEnabled(false);
 #endif
+    connect(this, &QDialog::accepted, [this](){
+        QSettings settings;
+        model->node().mapPort(settings.value("fUseUPnP").toBool());
+    });
 
     ui->proxyIp->setEnabled(false);
     ui->proxyPort->setEnabled(false);

src/qt/optionsmodel.cpp

@@ -355,7 +355,6 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
             break;
         case MapPortUPnP: // core option - can be changed on-the-fly
             settings.setValue("fUseUPnP", value.toBool());
-            node().mapPort(value.toBool());
             break;
         case MinimizeOnClose:
             fMinimizeOnClose = value.toBool();