Fixes: NB#250742 Low power mode UI appears black
Fixes: NB#250742 Low power mode UI appears black

  * MCompositeManagerPrivate::sendSyntheticVisibilityEventsForOurBabies():
    Clear the keep_black flag if lpm is covering, otherwise
    possiblyUnredirectTopmostWindow() won't do its job and
    the window will stay redirected but untracked.

nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor,nemomobile-graveyard/mcompositor