failover attention message is only for hard failover

Change-Id: Icdb20e449f9c638d50f144e86f751738ac0b3954
Reviewed-on: http://review.couchbase.org/37704
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>