QMenuPrivate: Make sloppyDelayTimer non-static

QMenuPrivate: Make sloppyDelayTimer non-static

Keeping the timer static would trigger warnings when enabling
SH_Menu_SloppySubMenus in QCommonStyle in a forthcoming patch.
This would happen if we opened a second level submenu quickly
enough and get the mouse event handler to reset the timer its
parent menu started.

This is a backport of Ia768603b40b219f87138c60a595c65ef408761ae
from qt/qtbase.

Change-Id: Ia7e9a94b3445d9362a60a36d5e4dda878ab0f7a5
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>