Remove unused variable reported by Sonar

Author: CarolynRountree

core/src/main/python/discover.py

@@ -373,7 +373,7 @@ def __check_and_customize_model(model, model_context):
         validator = Validator(model_context, wlst_mode=__wlst_mode)
 
         # no variables are generated by the discover tool
-        return_code = validator.validate_in_tool_mode(model.get_model(), variables_file_name=None,
+        validator.validate_in_tool_mode(model.get_model(), variables_file_name=None,
                                                       archive_file_name=model_context.get_archive_file_name())
     except ValidateException, ex:
         __logger.warning('WLSDPLY-06015', ex.getLocalizedMessage(), class_name=_class_name, method_name=_method_name)