Simplifying scheduler

Removing unnecessary code and variables
Sure, perhaps we can just update clusterState as we get the TaskStatuses back from reconciliation. It is possible that nodes/tasks have failed in the time between master failover, but reconciliation should return a TASK_LOST that we can use to update clusterState.
The other scenario is that the scheduler itself has failed over, at which point it will start up with an empty clusterState that we'll have to fill in from reconciliation.
We can figure it out then. Feel free to merge.