popover: Don't restore stale default widget
popover: Don't restore stale default widget

Only restore the saved default widget if the default hasn't been
changed while the popover was visible.

alexlarsson/gtk,jadahl/gtk,grubersjoe/adwaita,chergert/gtk,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,alexlarsson/gtk,chergert/gtk,chergert/gtk,davidgumberg/gtk,grubersjoe/adwaita,davidgumberg/gtk,davidgumberg/gtk,jadahl/gtk,alexlarsson/gtk,davidgumberg/gtk,grubersjoe/adwaita,jigpu/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,chergert/gtk,grubersjoe/adwaita,alexlarsson/gtk,jadahl/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,jigpu/gtk,davidgumberg/gtk,jadahl/gtk,grubersjoe/adwaita,jigpu/gtk,jigpu/gtk,davidgumberg/gtk,alexlarsson/gtk,jigpu/gtk,grubersjoe/adwaita,chergert/gtk,grubersjoe/adwaita,jigpu/gtk,jadahl/gtk,davidgumberg/gtk,alexlarsson/gtk