user32: in MENU_SuspendPopup() make sure the right message is removed

[Rein Klazes]

Hi,

This fixes a bug in Silkypix (see bug 17695). During menu tracking with
the keyboard, the application posts WM_KICKIDLE messages in the
WM_MENUSELECT handler. These are removed in wine's menu code, where it
expects to remove a keyboard message. So those messages never get
removed, and are processed ad infinitum...

Rein.