Fix to handling of partition merges

- In the case where host map state goes out of sync contentsSet needs to restore DB connections
- When restoring host map state after partitions take the union of all host map states as the outcome (and prune it later if needed)
- On a viewChange which removes a host from the view immediately trigger deactivation of the DB connections for that host.
Merge branch 'dev/grze/thefix' into testing