Use default member initialization in Compositor consistently

src/composite.cpp

@@ -112,9 +112,6 @@ private:
 
 Compositor::Compositor(QObject* workspace)
     : QObject(workspace)
-    , m_state(State::Off)
-    , m_selectionOwner(nullptr)
-    , m_scene(nullptr)
 {
     connect(options, &Options::configChanged, this, &Compositor::configChanged);
     connect(options, &Options::animationSpeedChanged, this, &Compositor::configChanged);

src/composite.h

@@ -135,13 +135,12 @@ private:
     bool attemptOpenGLCompositing();
     bool attemptQPainterCompositing();
 
-    State m_state;
-
-    CompositorSelectionOwner *m_selectionOwner;
+    State m_state = State::Off;
+    CompositorSelectionOwner *m_selectionOwner = nullptr;
     QTimer m_releaseSelectionTimer;
     QList<xcb_atom_t> m_unusedSupportProperties;
     QTimer m_unusedSupportPropertyTimer;
-    Scene *m_scene;
+    Scene *m_scene = nullptr;
     RenderBackend *m_backend = nullptr;
     QMap<RenderLoop *, AbstractOutput *> m_renderLoops;
 };