bgo#675421 - Set the wm_role on GtkFileChooserDialog
bgo#675421 - Set the wm_role on GtkFileChooserDialog

The window's role is 'GtkFileChooserDialog', so that window managers can match it
for positioning.

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

johne53/MB3Gtk-2,johne53/MB3Gtk-2,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,johne53/MB3Gtk-2,Distrotech/gtk