memcached crash during during online upgrade 2.5.0->3.0.1

newupgradetests.MultiNodesUpgradeTests.online_upgrade_rebalance_in_with_ops,initial_version=2.5.0-1059-rel,sasl_buckets=1,standard_buckets=1,items=10000,nodes_init=2,nodes_in=1,nodes_out=1,ddocs-num=1,upgrade_version=3.0.1-1360-rel,initial_vbuckets=512

1) 2 nodes cluster with 2.5.0
2) add one 3.0.1 node and remove 1 of 2.5.0. Rebalance. Rebalance fails

{u'node': u'ns_1@10.6.2.80', u'code': 2, u'text': u'Rebalance exited with reason {unexpected_exit,\n {\'EXIT\',<0.3885.0>,\n {bulk_set_vbucket_state_failed,\n [{\'ns_1@10.6.2.80\',\n {\'EXIT\',\n {{badmatch,wrong_rebalancer_pid},\n [{janitor_agent,set_vbucket_state,7,\n [

{file,"src/janitor_agent.erl"},\n {line,416}]},\n {janitor_agent,\n \'bulk_set_vbucket_state/4-fun-0\',4,\n [{file,"src/janitor_agent.erl"}

,\n

{line,403}]},\n {misc,\'parallel_map/3-fun-0\',4,\n [{file,"src/misc.erl"},\n {line,86}]}]}}}]}}}\n', u'shortText': u'message', u'serverTime': u'2014-10-02T18:50:30.818Z', u'module': u'ns_orchestrator', u'tstamp': 1412301030818, u'type': u'info'}
[2014-10-02 18:48:03,303] - [rest_client:2034] ERROR - {u'node': u'ns_1@10.6.2.80', u'code': 0, u'text': u'<0.3881.0> exited with {unexpected_exit,\n {\'EXIT\',<0.3885.0>,\n {bulk_set_vbucket_state_failed,\n [{\'ns_1@10.6.2.80\',\n {\'EXIT\',\n {{badmatch,wrong_rebalancer_pid},\n [{janitor_agent,set_vbucket_state,7,\n [{file,"src/janitor_agent.erl"},{line,416}]},\n {janitor_agent,\n \'bulk_set_vbucket_state/4-fun-0\',4,\n [{file,"src/janitor_agent.erl"},{line,403}

]},\n {misc,\'parallel_map/3-fun-0\',4,\n [

{file,"src/misc.erl"}

,

{line,86}

]}]}}}]}}}', u'shortText': u'message', u'serverTime': u'2014-10-02T18:50:25.749Z', u'module': u'ns_vbucket_mover', u'tstamp': 1412301025749, u'type': u'critical'}

will attach cbcollects