Welcome: Initialize pointers

Change-Id: Ib64fb5a316324c36957ea64c493674cfa85674cd
Reviewed-by: hjk <hjk@qt.io>

src/plugins/coreplugin/iwelcomepage.cpp

@@ -98,8 +98,8 @@ public:
     void doUpdate(bool cursorInside);
 
     WelcomePageButton *q;
-    QHBoxLayout *m_layout;
-    QLabel *m_label;
+    QHBoxLayout *m_layout = nullptr;
+    QLabel *m_label = nullptr;
     QLabel *m_icon = nullptr;
 
     std::function<void()> onClicked;