file chooser: Fix gtk_file_chooser_set_show_hidden
file chooser: Fix gtk_file_chooser_set_show_hidden

We should not override an explicitly set show-hidden value
when loading the setting.

https://bugzilla.gnome.org/show_bug.cgi?id=610925

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