Wrong balance if there are multiple invalid Replicas when using MoveDisallowedReplicas

[kjelle]

Hello.
Nice program you created.

If you got e.g. 3 replicas, and 2 of them are non-existant Broker IDs, and you run with maxReassign:1, it will propose a move which uses one of the invalid broker IDs, and the reassignment failes.

And, if you run with maxReassign:2, it will fix the second one in the second run of MoveDisallowedReplicas. However, on the JSON printout it prints both moves, with the last value, twice. That isnt a problem, but it could generate a x-times larger JSON than neccessary.

I am currently looking into how you can fix it.

[CAFxX]

@kjelle I just fixed an issue in MoveDisallowedReplicas that could result in the step failing or returning suboptimal results; can you try again with current master? If it still reproduces, can you submit a test case? (see in balancer_test.go)