button: Ensure the button is "left" when a gesture is cancelled
button: Ensure the button is "left" when a gesture is cancelled

This prevents from stale widget states if the gesture happens to be
cancelled mid-press.

jadahl/gtk,Adamovskiy/gtk,jigpu/gtk,chergert/gtk,grubersjoe/adwaita,davidgumberg/gtk,Lyude/gtk-,davidgumberg/gtk,grubersjoe/adwaita,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,ahodesuka/gtk,davidgumberg/gtk,Adamovskiy/gtk,alexlarsson/gtk,jigpu/gtk,Lyude/gtk-,Lyude/gtk-,davidgumberg/gtk,jigpu/gtk,alexlarsson/gtk,Adamovskiy/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,Adamovskiy/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,davidgumberg/gtk,alexlarsson/gtk,Adamovskiy/gtk,alexlarsson/gtk,jadahl/gtk,Adamovskiy/gtk,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,chergert/gtk,Lyude/gtk-,Lyude/gtk-,ahodesuka/gtk,ahodesuka/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk,jadahl/gtk,chergert/gtk,Adamovskiy/gtk,Lyude/gtk-,Lyude/gtk-,jadahl/gtk,ahodesuka/gtk,jadahl/gtk,jadahl/gtk,jigpu/gtk,ahodesuka/gtk,chergert/gtk,alexlarsson/gtk,alexlarsson/gtk,jigpu/gtk,ahodesuka/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,Adamovskiy/gtk,grubersjoe/adwaita