CBQE-0: minor fix upgrade with autofailover_alerts verification

Change-Id: Ib30ef0b2df5e32683c94d203947f8d22f26bf320
Reviewed-on: http://review.couchbase.org/26427
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>