about-dialog: don't set a margin around the license area

Make it consistent with the credits page.

https://bugzilla.gnome.org/show_bug.cgi?id=670077

gtk/gtkaboutdialog.c

@@ -2422,7 +2422,6 @@ create_license_page (GtkAboutDialog *about)
   priv->license_page = gtk_notebook_append_page (GTK_NOTEBOOK (priv->notebook), page_vbox, NULL);
 
   sw = gtk_scrolled_window_new (NULL, NULL);
-  gtk_container_set_border_width (GTK_CONTAINER (sw), 5);
   gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (sw), GTK_SHADOW_IN);
   gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
                                   GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC);