Hard coded endpoint address for OSS is removed
Hard coded endpoint address for OSS is removed

Due to endpoint address is already set in .py(oss_param['endpoint'] = 'http://oss-cn-hangzhou-zmf.aliyuncs.com') and not able to change via options if some other location OSS is used, hence removing hard coded value.
kubeflow/xgboost-operator,kubeflow/xgboost-operator,kubeflow/xgboost-operator