[seahorse] Use fallback icons if symbolic icons are not available

[Stefan Walter <stefw src gnome org>]

commit d3ceb7766b90101f374f1ea50f1a492db137b50a
Author: Stef Walter <stefw gnome org>
Date:   Fri Nov 9 11:14:45 2012 +0100

    Use fallback icons if symbolic icons are not available
    
     * Avoids crash
    
    https://bugzilla.gnome.org/show_bug.cgi?id=687967

 src/seahorse-sidebar.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/seahorse-sidebar.c b/src/seahorse-sidebar.c
index 9f0305a..13e615c 100644
--- a/src/seahorse-sidebar.c
+++ b/src/seahorse-sidebar.c
@@ -203,7 +203,8 @@ ensure_sidebar_pixbufs (SeahorseSidebar *self)
 
 	/* Lock icon */
 	icon = g_themed_icon_new_with_default_fallbacks ("changes-prevent-symbolic");
-	icon_info = gtk_icon_theme_lookup_by_gicon (icon_theme, icon, self->action_button_size, 0);
+	icon_info = gtk_icon_theme_lookup_by_gicon (icon_theme, icon, self->action_button_size, GTK_ICON_LOOKUP_GENERIC_FALLBACK);
+	g_return_if_fail (icon_info != NULL);
 	if (!self->pixbuf_lock)
 		self->pixbuf_lock = gtk_icon_info_load_symbolic_for_context (icon_info, style, NULL, NULL);
 	if (!self->pixbuf_lock_l)
@@ -213,7 +214,8 @@ ensure_sidebar_pixbufs (SeahorseSidebar *self)
 
 	/* Unlock icon */
 	icon = g_themed_icon_new_with_default_fallbacks ("changes-allow-symbolic");
-	icon_info = gtk_icon_theme_lookup_by_gicon (icon_theme, icon, self->action_button_size, 0);
+	icon_info = gtk_icon_theme_lookup_by_gicon (icon_theme, icon, self->action_button_size, GTK_ICON_LOOKUP_GENERIC_FALLBACK);
+	g_return_if_fail (icon_info != NULL);
 	if (!self->pixbuf_unlock)
 		self->pixbuf_unlock = gtk_icon_info_load_symbolic_for_context (icon_info, style, NULL, NULL);
 	if (!self->pixbuf_unlock_l)