Fix docs to reflect latest API

Documentation error on pages at http://developer.couchbase.com/documentation/server/4.5/connectors/spark-2.0/working-with-rdds.html
Refers to Query class which was renamed a while ago.

Docs say use terminology like:
{{val query = "SELECT name FROM `travel-sample` WHERE type = 'airline' ORDER BY name ASC LIMIT 10"
sc
  .couchbaseQuery(Query.simple(query))
  .collect()
  .foreach(println)
}}

Should be N1qlQuery, after importing:

{{import com.couchbase.client.java.query._
sc.couchbaseQuery(N1qlQuery.simple(query))
}}