MB-11825: ignore unexpected infos in new_ns_replicas_builder

Change-Id: Ib0e2e8abf44510b0dd62f96b05ee5cbcb581b95e
Reviewed-on: http://review.couchbase.org/39908
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>