Make qgis_sip_uptodate happy

python/core/auto_generated/qgsrulebasedlabeling.sip.in

@@ -37,7 +37,7 @@ class QgsRuleBasedLabeling : QgsAbstractVectorLayerLabeling
       public:
         Rule( QgsPalLayerSettings *settings /Transfer/, int maximumScale = 0, int minimumScale = 0, const QString &filterExp = QString(), const QString &description = QString(), bool elseRule = false );
 %Docstring
-takes ownership of settings
+takes ownership of settings, settings may be None
 %End
         ~Rule();