The number of container partitions that are in handoff locations can
be used to track progress of a container ring rebalance. However,
container DBs are sometimes deliberately created in handoff locations:
the sharder creates shard container DBs while cleaving and also while
moving misplaced objects; the container-replicator creates DBs to feed
misplaced objects to the reconciler. These DBs can distorts insights
into rebalance progress. Emitting stats will help quantify any such
distortion.
New sharder stats are:
cleaved_db_created
cleaved_db_exists
misplaced_db_created
misplaced_db_exists
New container-replicator stats are:
reconciler_db_created
reconciler_db_exists
Change-Id: Ia43e91a545a822cace41a0e814ab6c3bd89f8402
517738ac9a