MB-11730: fixed buckets list details section style

Change-Id: Ibe9d9c6990f0b131f1bc9bb722f90fb7c475b296
Reviewed-on: http://review.couchbase.org/39408
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>