MB-100: cut unused config upgrade from 1.8.1 to 2.0

Change-Id: Ib4665c3364f5e56d65dd2528f385fc5aafc6a3ba
Reviewed-on: http://review.couchbase.org/29945
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>