[processing] fix handling of boolean parameters in modeller

Author: alexbruy

python/plugins/processing/modeler/ModelerParametersDialog.py

@@ -269,6 +269,8 @@ def getWidgetFromParameter(self, param):
                 item.addItem(self.resolveValueDescription(layer), layer)
         elif isinstance(param, ParameterBoolean):
             item = QComboBox()
+            item.addItem('Yes')
+            item.addItem('No')
             bools = self.getAvailableValuesOfType(ParameterBoolean, None)
             for b in bools:
                 item.addItem(self.resolveValueDescription(b), b)