Fix warning about unhandled enumeration value.

Change-Id: Ic22a9bddfa04c286f359bc29e1d5d1ec8ef98ecc
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>

src/gui/kernel/qguiapplication.cpp

@@ -1648,6 +1648,8 @@ void QGuiApplicationPrivate::processApplicationStateChangedEvent(QWindowSystemIn
         QEvent appDeactivate(QEvent::ApplicationDeactivate);
         qApp->sendSpontaneousEvent(qApp, &appDeactivate);
         break; }
+    default:
+        break;
     }
 }