[glom] Simplify a line of code

[Murray Cumming <murrayc src gnome org>]

commit 0730af09d6035e9b544a5a8e2117c23c6fb190bd
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Aug 5 19:48:53 2011 +0200

    Simplify a line of code

 .../print_layouts/window_print_layout_edit.cc      |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glom/mode_design/print_layouts/window_print_layout_edit.cc b/glom/mode_design/print_layouts/window_print_layout_edit.cc
index 62bb99a..0e0536f 100644
--- a/glom/mode_design/print_layouts/window_print_layout_edit.cc
+++ b/glom/mode_design/print_layouts/window_print_layout_edit.cc
@@ -247,7 +247,7 @@ Glib::RefPtr<Gdk::Pixbuf> Window_PrintLayout_Edit::get_icon_for_toolbar_item(Gtk
     return result;
 
   const Gtk::StockID stock_id = action->property_stock_id();
-  if(!(stock_id.get_string().empty())) //The operator bool() is only in later versions of gtkmm 2.*.x
+  if(stock_id)
   {
     result = item.render_icon_pixbuf(stock_id, Gtk::ICON_SIZE_LARGE_TOOLBAR);
   }