Blocker Description
As part of KAFKA-513, we added controllerId in LeaderAndIsrRequest. We should add that to all requests sent by the controller, such as StopReplicaRequest.
Other small issues that can be taken care of by this jira:
1. The string "state.change.logger" is used in many places. We should create a constant val and reuse the val to avoid human mistakes.
2. Remove the private constructor from ControllerChannelManager.
3. Remove default from jsonFileOpt in PreferredReplicaLeaderElectionCommand, because the default is only used to indicate an absense of a legitimate jsonFile. We can check the same using if(options.has(jsonFileOpt))