Retry of failed swap rebalance fails with {{{\'EXIT\',< {{wait_seqno_persisted_failed

./testrunner -i /tmp/testexec.3084.ini -p get-cbcollect-info=True -t swaprebalance.SwapRebalanceFailedTests.test_failed_swap_rebalance,replica=1,num-buckets=4,num-swap=2,swap-orchestrator=True,percentage_progress=30,GROUP=P0

{u'node': u'ns_1@172.23.106.6', u'code': 0, u'text': u'Rebalance exited with reason {mover_crashed,\n                              {unexpected_exit,\n                               {\'EXIT\',<0.1693.36>,\n                                {{wait_seqno_persisted_failed,"bucket-2",906,\n                                  0,\n                                  [{\'ns_1@172.23.106.8\',\n                                    {\'EXIT\',\n                                     {{{child_interrupted,\n                                        {\'EXIT\',<25253.18204.4>,\n                                         socket_closed}},\n                                       [{dcp_replicator,spawn_and_wait,1,\n                                         [{file,"src/dcp_replicator.erl"},\n                                          {line,249}]},\n                                        {dcp_replicator,handle_call,3,\n                                         [{file,"src/dcp_replicator.erl"},\n                                          {line,127}]},\n                                        {gen_server,try_handle_call,4,\n                                         [{file,"gen_server.erl"},{line,636}]},\n                                        {gen_server,handle_msg,6,\n                                         [{file,"gen_server.erl"},{line,665}]},\n                                        {proc_lib,init_p_do_apply,3,\n                                         [{file,"proc_lib.erl"},{line,247}]}]},\n                                      {gen_server,call,\n                                       [{\'janitor_agent-bucket-2\',\n                                         \'ns_1@172.23.106.8\'},\n                                        {if_rebalance,<0.19815.34>,\n                                         {wait_seqno_persisted,906,0}},\n                                        infinity]}}}}]},\n                                 [{ns_single_vbucket_mover,\n                                   \'-wait_seqno_persisted_many/5-fun-2-\',5,\n                                   [{file,"src/ns_single_vbucket_mover.erl"},\n                                    {line,488}]},\n                                  {proc_lib,init_p,3,\n                                   [{file,"proc_lib.erl"},{line,232}]}]}}}}.\nRebalance Operation Id = 05371dfb9070e86ed82e49c201b45e4d', u'shortText': u'message', u'serverTime': u'2019-08-02T05:55:31.160Z', u'module': u'ns_orchestrator', u'tstamp': 1564750531160, u'type': u'critical'}