Fix compiler warnings, add override

Change-Id: I547e94213f4b4d2c3ca3aeaa06330069e6311043
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

tests/auto/customization/tst_customization.cpp

@@ -113,7 +113,7 @@ class tst_customization : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
     void cleanupTestCase();
 
     void init();

tests/auto/focus/tst_focus.cpp

@@ -55,7 +55,7 @@ class tst_focus : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
 
     void navigation_data();
     void navigation();

tests/auto/palette/tst_palette.cpp

@@ -63,7 +63,7 @@ class tst_palette : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
 
     void palette_data();
     void palette();

tests/auto/qquickcontrol/tst_qquickcontrol.cpp

@@ -49,7 +49,7 @@ class tst_QQuickControl : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
     void flickable();
 
 private:

tests/auto/qquickdrawer/tst_qquickdrawer.cpp

@@ -60,7 +60,7 @@ class tst_QQuickDrawer : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
 
     void defaults();
     void invalidEdge();

tests/auto/qquickiconimage/tst_qquickiconimage.cpp

@@ -53,7 +53,7 @@ public:
     tst_qquickiconimage();
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
     void defaults();
     void nameBindingSourceSize();
     void nameBindingSourceSizeWidthHeight();
@@ -496,7 +496,7 @@ class TestImageProvider : public QQuickImageProvider
 public:
     TestImageProvider() : QQuickImageProvider(QQuickImageProvider::Pixmap) { }
 
-    QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize)
+    QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize) override
     {
         QSize defaultSize(32, 32);
         if (size)

tests/auto/qquickpopup/tst_qquickpopup.cpp

@@ -62,7 +62,7 @@ class tst_QQuickPopup : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
     void visible_data();
     void visible();
     void state();

tests/auto/styleimports/tst_styleimports.cpp

@@ -52,7 +52,7 @@ class tst_StyleImports : public QQmlDataTest
     Q_OBJECT
 
 private slots:
-    void initTestCase();
+    void initTestCase() override;
 
     void cleanup();