"WALs outstanding" message from CleanerChore is noisy

WARN level "WALs outstanding" from CleanerChore should be DEBUG and are not always correct.

I left a cluster configured for ITBLL (retaining all WALs for post hoc analysis) and in the morning found the master log full of "WALs outstanding" warnings from CleanerChore.

Should this really be a warning?

2018-05-09 16:42:03,893 WARN [node-1.cluster,16000,1525851521469_ChoreService_2] cleaner.CleanerChore: WALs outstanding under hdfs://node-1.cluster/hbase/oldWALs

If someone has configured really long WAL retention then having WALs in oldWALs will be normal.

Also, it seems the warning is sometimes incorrect.

2018-05-09 16:42:24,751 WARN [node-1.cluster,16000,1525851521469_ChoreService_1] cleaner.CleanerChore: WALs outstanding under hdfs://node-1.cluster/hbase/archive

There are no WALs under archive/.

Even at DEBUG level, if it is not correct, then it can lead an operator to be concerned about nothing, so better to just remove it.