Remove reimplementations of removed features

Avoid the "marked ‘override’, but does not override" compile error.

Change-Id: I4b125f1951614045781f3059fbc5cb65dd26775c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/widgets/widgets/qabstractspinbox.cpp

@@ -1246,11 +1246,9 @@ void QAbstractSpinBox::timerEvent(QTimerEvent *event)
     \reimp
 */
 
+#if QT_CONFIG(contextmenu)
 void QAbstractSpinBox::contextMenuEvent(QContextMenuEvent *event)
 {
-#ifdef QT_NO_CONTEXTMENU
-    Q_UNUSED(event);
-#else
     Q_D(QAbstractSpinBox);
 
     QPointer<QMenu> menu = d->edit->createStandardContextMenu();
@@ -1286,8 +1284,8 @@ void QAbstractSpinBox::contextMenuEvent(QContextMenuEvent *event)
         }
     }
     event->accept();
-#endif // QT_NO_CONTEXTMENU
 }
+#endif // QT_CONFIG(contextmenu)
 
 /*!
     \reimp

src/widgets/widgets/qabstractspinbox.h

@@ -142,7 +142,9 @@ protected:
 #endif
     void focusInEvent(QFocusEvent *event) override;
     void focusOutEvent(QFocusEvent *event) override;
+#if QT_CONFIG(contextmenu)
     void contextMenuEvent(QContextMenuEvent *event) override;
+#endif
     void changeEvent(QEvent *event) override;
     void closeEvent(QCloseEvent *event) override;
     void hideEvent(QHideEvent *event) override;