[gnome-screenshot] dialog: use correct pointer as GtkWidget

[Cosimo Cecchi <cosimoc src gnome org>]

commit 55d2613bbce30f88575b524a65933af58d756ec8
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Jul 24 13:31:51 2019 +0200

    dialog: use correct pointer as GtkWidget
    
    Avoids critical warnings.

 src/screenshot-dialog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/screenshot-dialog.c b/src/screenshot-dialog.c
index 9527b77..40e560b 100644
--- a/src/screenshot-dialog.c
+++ b/src/screenshot-dialog.c
@@ -318,7 +318,7 @@ screenshot_dialog_set_busy (ScreenshotDialog *dialog,
       g_autoptr(GdkCursor) cursor = NULL;
       GdkDisplay *display;
       /* Change cursor to busy */
-      display = gtk_widget_get_display (GTK_WIDGET (dialog));
+      display = gtk_widget_get_display (GTK_WIDGET (dialog->dialog));
       cursor = gdk_cursor_new_for_display (display, GDK_WATCH);
       gdk_window_set_cursor (window, cursor);
     }