Lint
Clean up a race on the cleaner_stop flag; declaring it volatile should be
sufficient, all we care about is if it eventually gets set, and there is
eventually a run after that to clean out the cache.

Rework kvs_dump() to dump to a specific output file based on the tag.

Change the operation/byte limits for the cleaner to be roughly analogous
to each other, I hesitate to call this "tuning".