Bug：windows环境下配置hdfsWriter，由于windows文件分隔符为\，会导致写完hdfs删除临时目录的时候，误删数据库

dataX日志如下：
09:30:26.485 [job-0] INFO  c.a.d.p.w.hdfswriter.HdfsWriter$Job - start rename file [hdfs://hacluster/user/hive/warehouse/ods.db/test_maozl__504dceda_c549_49c5_b914_cf6483664813\file__b1d2c12d_4bf2_494c_8e1e_6f4be4fd8b37] to file [hdfs://hacluster/user/hive/warehouse/ods.db/test_maozl\file__b1d2c12d_4bf2_494c_8e1e_6f4be4fd8b37].
09:30:26.524 [job-0] INFO  c.a.d.p.w.hdfswriter.HdfsWriter$Job - finish rename file [hdfs://hacluster/user/hive/warehouse/ods.db/test_maozl__504dceda_c549_49c5_b914_cf6483664813\file__b1d2c12d_4bf2_494c_8e1e_6f4be4fd8b37] to file [hdfs://hacluster/user/hive/warehouse/ods.db/test_maozl\file__b1d2c12d_4bf2_494c_8e1e_6f4be4fd8b37].
09:30:26.524 [job-0] INFO  c.a.d.p.w.hdfswriter.HdfsWriter$Job - start delete tmp dir [hdfs://hacluster/user/hive/warehouse/ods.db].
09:30:26.551 [job-0] INFO  c.a.d.p.w.hdfswriter.HdfsWriter$Job - finish delete tmp dir [hdfs://hacluster/user/hive/warehouse/ods.db].

通过调试发现，是由于临时文件的目录里包含windows的文件分隔符\，导致删除临时文件的时候，hadoop的Path.getParent()找到的路径为hdfs://hacluster/user/hive/warehouse/ods.db，进而直接把数据库给删掉了。

修改方法：
将HdfsWriter里的文件分割符替换为IOUtils.DIR_SEPARATOR_UNIX

Start in HdfsWriter by tracing how temporary file paths are assembled on Windows and how Path.getParent() is used during temporary-directory deletion. Compare the logged paths with the reported deletion behavior, then verify that using IOUtils.DIR_SEPARATOR_UNIX prevents the parent HDFS database directory from being selected for deletion.

Written by the indexing model from the issue text.