CBQE-0: fix rebalance_in_with_cluster_password_change

Change-Id: I14b0a2cb831f764ec6e58fb7727a36dad3f67d54
Reviewed-on: http://review.couchbase.org/33484
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: buildbot <build@couchbase.com>