Ignore drained nodes when rebalancing

When running `rabbitmq-queues rebalance`, drained nodes (nodes in maintenance mode) should not recive QQ leaders nor CMQ masters.

Author: mkuratczyk

deps/rabbit/src/rabbit_amqqueue.erl

@@ -504,7 +504,7 @@ maybe_migrate(ByNode, MaxQueuesDesired, [N | Nodes]) ->
         [{_, Q, false} = Queue | Queues] = All when length(All) > MaxQueuesDesired ->
             Name = amqqueue:get_name(Q),
             Module = rebalance_module(Q),
-            Candidates = Module:get_replicas(Q) -- [N],
+            Candidates = rabbit_maintenance:filter_out_drained_nodes_consistent_read(Module:get_replicas(Q) -- [N]),
             case Candidates of
                 [] ->
                     {not_migrated, update_not_migrated_queue(N, Queue, Queues, ByNode)};