Qt: correctly forward wheeling events on Win32

Closes blocker #3262
(cherry picked from commit d24e45887e24bb45da8c7a55263a47d0bf548da3)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/interface_widgets.cpp

@@ -264,6 +264,12 @@ bool VideoWidget::eventFilter(QObject *obj, QEvent *event)
             emit keyPressed( static_cast<QKeyEvent *>(event) );
             return true;
         }
+        else if( event->type() == QEvent::Wheel )
+        {
+            int i_vlckey = qtWheelEventToVLCKey( static_cast<QWheelEvent *>(event) );
+            var_SetInteger( p_intf->p_libvlc, "key-pressed", i_vlckey );
+            return true;
+        }
     }
     return false;
 }