dropped ui support for pre-2.0 cluster compat modes

Change-Id: I631ee2f96b2bef928ca0f22c5cb29d682d46fe93
Reviewed-on: http://review.couchbase.org/33712
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Artem Stemkovski <artem@couchbase.com>