文本读取，unstructured-storage-util工具类中的BUG

问题：
在txtFileReader中
配置csvReaderConfig不生效

排查：
public static HashMap csvReaderConfigMap; 仅定义未赋值

在执行时可以通过readerSliceConfig.getMapConfiguration(Key.CSV_READER_CONFIG)获取到配置。但是未进行赋值就进行了判断。

解决：
在readFromStream和获取配置时加上即可
if(null == UnstructuredStorageReaderUtil.csvReaderConfigMap){
UnstructuredStorageReaderUtil.csvReaderConfigMap = (HashMap)readerSliceConfig.getMapConfiguration(Key.CSV_READER_CONFIG);
}

Start in UnstructuredStorageReaderUtil and inspect txtFileReader, especially readFromStream and the CSV configuration lookup. Reproduce the issue with a csvReaderConfig setting, then verify that the configured values are assigned and take effect during text reading.

Written by the indexing model from the issue text.