filechooserbutton: Simplify the code to preserve the selection while the dialog is running
filechooserbutton: Simplify the code to preserve the selection while the dialog is running

It used to fetch a possibly multiple selection from the GtkFileChooserDialog, and then
pick just the first item from the selection list.  But since GtkFileChooserButton
operates in single-selection mode only, it can simply use gtk_file_chooser_get_file()
instead.

Also, the right way to reset the selection for GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER
is with gtk_file_chooser_select_file(), not with _set_current_folder_file().

Signed-off-by: Federico Mena Quintero <4999915a961edfd7686112c2935288e1266eae14@gnome.org>

jessevdk/gtk,chergert/gtk,msteinert/gtk,davidgumberg/gtk,davidgumberg/gtk,bratsche/gtk-,jessevdk/gtk,Lyude/gtk-,ebassi/gtk,jigpu/gtk,alexlarsson/gtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,msteinert/gtk,jadahl/gtk,Lyude/gtk-,jigpu/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,Adamovskiy/gtk,jadahl/gtk,jigpu/gtk,ebassi/gtk,Lyude/gtk-,Distrotech/gtk2,alexlarsson/gtk,grubersjoe/adwaita,chergert/gtk,grubersjoe/adwaita,chergert/gtk,bratsche/gtk-,bratsche/gtk-,ahodesuka/gtk,jigpu/gtk,ebassi/gtk,jessevdk/gtk,msteinert/gtk,davidt/gtk,jessevdk/gtk,jadahl/gtk,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,ahodesuka/gtk,Adamovskiy/gtk,davidgumberg/gtk,bratsche/gtk-,jigpu/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,davidt/gtk,Lyude/gtk-,alexlarsson/gtk,msteinert/gtk,Lyude/gtk-,Distrotech/gtk2,grubersjoe/adwaita,Lyude/gtk-,ahodesuka/gtk,ahodesuka/gtk,Adamovskiy/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,jessevdk/gtk,Lyude/gtk-,grubersjoe/adwaita,jadahl/gtk,jigpu/gtk,chergert/gtk,chergert/gtk,chergert/gtk,Distrotech/gtk2,jadahl/gtk,ebassi/gtk,davidgumberg/gtk,grubersjoe/adwaita,bratsche/gtk-,jadahl/gtk,davidt/gtk,msteinert/gtk,Lyude/gtk-,davidt/gtk,chergert/gtk,alexlarsson/gtk,chergert/gtk,jigpu/gtk,jigpu/gtk,davidgumberg/gtk,Distrotech/gtk2,ebassi/gtk,ebassi/gtk,davidt/gtk,Distrotech/gtk2,Adamovskiy/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,Sidnioulz/SandboxGtk,alexlarsson/gtk,msteinert/gtk,davidgumberg/gtk,bratsche/gtk-,jessevdk/gtk,Sidnioulz/SandboxGtk,Distrotech/gtk2,Adamovskiy/gtk,davidgumberg/gtk,grubersjoe/adwaita,davidt/gtk,ahodesuka/gtk,grubersjoe/adwaita