Recovered WAL directories not getting cleaned up

In HBASE-20734 we moved the recovered.edits onto the wal file system but when constructing the directory we missed the BASE_NAMESPACE_DIR('data'). So when using the default config, you will find that there are lots of new directories at the same level with the 'data' directory. In this issue, we add the BASE_NAMESPACE_DIR back, and also try our best to clean up the wrong directories. But we can only clean up the region level directories, so if you want a clean fs layout on HDFS you still need to manually delete the empty directories at the same level with 'data'. The effect versions are 2.2.0, 2.1.[1-5], 1.4.[8-10], 1.3.[3-5].