Fix crash when icon of property is Null

bus/factoryproxy.c

@@ -176,7 +176,8 @@ bus_factory_proxy_create_engine (BusFactoryProxy *factory,
     g_variant_get (retval, "(&o)", &object_path);
     GDBusConnection *connection = g_dbus_proxy_get_connection ((GDBusProxy *) factory);
     BusEngineProxy *engine = bus_engine_proxy_new (object_path,
-                    desc, bus_connection_lookup (connection));
+                                                   desc,
+                                                   bus_connection_lookup (connection));
     g_variant_unref (retval);
     return engine;
 }

src/ibusproperty.c

@@ -243,7 +243,7 @@ ibus_property_set_icon (IBusProperty *prop,
     g_assert (IBUS_IS_PROPERTY (prop));
 
     g_free (prop->icon);
-    prop->icon = g_strdup (icon);
+    prop->icon = g_strdup (icon != NULL ? icon : "");
 }
 
 void