[Magma] Rebalance exited with reason buckets_shutdown_wait_failed

rebalance_report_20220314T223148.json:

{"stageInfo":{"data":{"startTime":"2022-03-14T15:30:48.099-07:00","completedTime":false,"timeTaken":60280}},"rebalanceId":"966b008ec2d7d181ce4f40571d563618","nodesInfo":{"active_nodes":["ns_1@172.23.100.38","ns_1@172.23.100.39"],"keep_nodes":["ns_1@172.23.100.38"],"eject_nodes":["ns_1@172.23.100.39"],"delta_nodes":[],"failed_nodes":[]},"masterNode":"ns_1@172.23.100.38","startTime":"2022-03-14T15:30:48.098-07:00","completedTime":"2022-03-14T15:31:48.379-07:00","timeTaken":60281,"completionMessage":"Rebalance exited with reason {buckets_shutdown_wait_failed,\n                              [{'ns_1@172.23.100.38',\n                                {'EXIT',\n                                 {old_buckets_shutdown_wait_failed,\n                                  [\"default\"]}}}]}."}