ISPN-4711 Remoted commands to a dead master node can be re-forwarded to a valid backend
ISPN-4712 Mutable SearchFactory needs to be passed new types exclusively
ISPN-4713 Reject incoming Query RPCs on stopped and being-shutdown caches
ISPN-4714 Improve logging to trace IndexManager's lock promotion phases
ISPN-4715 Resolve race condition in Lock promotion of IndexManager