Fixed incorrect usage of `signals', `slots' in headers

Qt headers must use Q_SIGNALS, Q_SLOTS.

Reviewed-by: Jason McDonald
Change-Id: I54b3322befd8f133d44aa48f3aa7cd96785d2e24

src/declarative/items/qsgcanvas.h

@@ -75,7 +75,7 @@ public:
 
     QSGEngine *sceneGraphEngine() const;
 
-signals:
+Q_SIGNALS:
     void sceneGraphInitialized();
 
 protected:
@@ -100,7 +100,7 @@ protected:
     virtual void wheelEvent(QWheelEvent *);
 #endif
 
-private slots:
+private Q_SLOTS:
     void sceneGraphChanged();
     void maybeUpdate();
 

src/declarative/scenegraph/util/qsgengine.h

@@ -79,7 +79,7 @@ public:
     void setClearColor(const QColor &color);
     QColor clearColor() const;
 
-signals:
+Q_SIGNALS:
     void beforeRendering();
     void afterRendering();