gtk: set free_scale when setting zoom_fit

free_scale field tracks zoom-fit menu toggle state,
so we should keep them in sync ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
diff --git a/ui/gtk.c b/ui/gtk.c
index 322d112..2629d97 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -1782,6 +1782,7 @@
 
     if (dpy_ui_info_supported(vc->gfx.dcl.con)) {
         gtk_menu_item_activate(GTK_MENU_ITEM(s->zoom_fit_item));
+        s->free_scale = true;
     }
 
     return group;