range: No need to update mouse location when starting a drag
range: No need to update mouse location when starting a drag

The mouse position doesn't change here. Plus, all callers have just
updated it anyway.

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