MB-100: minor fix in autofailovertests logs

Change-Id: Ic81a3d5c1ee5253b2f8c94b0fac3cc570346cb29
Reviewed-on: http://review.couchbase.org/25663
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>