csd: Fix drag hightlight drawing
csd: Fix drag hightlight drawing

When making the entire window a drop target, as file-roller does,
we don't want to draw the drag highlight around the CSD window
decorations.
https://bugzilla.gnome.org/show_bug.cgi?id=728526
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ahodesuka/gtk,jigpu/gtk,msteinert/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,chergert/gtk,chergert/gtk,jessevdk/gtk,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,jigpu/gtk,Lyude/gtk-,Lyude/gtk-,grubersjoe/adwaita,Sidnioulz/SandboxGtk,msteinert/gtk,jessevdk/gtk,davidgumberg/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,ahodesuka/gtk,ahodesuka/gtk,alexlarsson/gtk,ahodesuka/gtk,jigpu/gtk,chergert/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,davidgumberg/gtk,Lyude/gtk-,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,jigpu/gtk,jessevdk/gtk,grubersjoe/adwaita,jessevdk/gtk,davidgumberg/gtk,chergert/gtk,msteinert/gtk,msteinert/gtk,chergert/gtk,msteinert/gtk,chergert/gtk,chergert/gtk,jessevdk/gtk,msteinert/gtk,Lyude/gtk-,jigpu/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,chergert/gtk,Lyude/gtk-,jadahl/gtk,alexlarsson/gtk,Adamovskiy/gtk,grubersjoe/adwaita,Lyude/gtk-,davidgumberg/gtk,jadahl/gtk,jigpu/gtk,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,Adamovskiy/gtk,jadahl/gtk,ahodesuka/gtk,Adamovskiy/gtk,jigpu/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jadahl/gtk,davidgumberg/gtk,ahodesuka/gtk,alexlarsson/gtk,jadahl/gtk,Lyude/gtk-,grubersjoe/adwaita,davidgumberg/gtk,jadahl/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,alexlarsson/gtk,jigpu/gtk,Sidnioulz/SandboxGtk,jessevdk/gtk