Gui: modernize C++: use default member init

src/Gui/GuiApplication.cpp

@@ -167,8 +167,6 @@ public:
     explicit Private(GUISingleApplication *q_ptr)
       : q_ptr(q_ptr)
       , timer(new QTimer(q_ptr))
-      , server(nullptr)
-      , running(false)
     {
         timer->setSingleShot(true);
         std::string exeName = App::Application::getExecutableName();
@@ -218,10 +216,10 @@ public:
 
     GUISingleApplication *q_ptr;
     QTimer *timer;
-    QLocalServer *server;
+    QLocalServer *server{nullptr};
     QString serverName;
     QList<QByteArray> messages;
-    bool running;
+    bool running{false};
 };
 
 GUISingleApplication::GUISingleApplication(int & argc, char ** argv)