wayland: Don't unset the selected mimetype on drop_reply
wayland: Don't unset the selected mimetype on drop_reply

gdk_wayland_drop_context_set_status() can't do much else currently besides
picking a mimetype (the first one is currently chosen). This may incorrectly
unset the mimetype chosen on .receive(), so the transfer is cancelled before
it even starts.

At the time drop_reply happens, we should have already picked a mimetype
along the way, so only cover for accepted=FALSE in order to unset it.

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