Qt: FSC: reset the OPACITY on EnterEvent.

(cherry picked from commit 7243c2e3)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/controller.cpp

@@ -952,6 +952,7 @@ void FullscreenControllerWidget::enterEvent( QEvent *event )
     p_hideTimer->stop();
 #if HAVE_TRANSPARENCY
     p_slowHideTimer->stop();
+    setWindowOpacity( DEFAULT_OPACITY );
 #endif
     event->accept();
 }