squash! ERP5Workflow: Remove unused variable_default_value...

squash! ERP5Workflow: Remove unused variable_default_value (variable_default_expression should be used instead).

product/ERP5Type/patches/DCWorkflow.py

@@ -1124,7 +1124,7 @@ def convertToERP5Workflow(self, temp_object=False):
       # default_expr has precedence over default_value if defined...
       elif variable_definition.default_value:
         if '/' not in variable_definition.default_value:
-          default_value = 'python: %s' % variable_definition.default_value
+          default_value = "python: '%s'" % variable_definition.default_value
         else:
           default_value = variable_definition.default_value
         variable.setVariableDefaultExpression(default_value)