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/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();