JCBC-527: support for cluster info.

Change-Id: I3018aa71565d2d27a584bc18cb813ca81ec30559
Reviewed-on: http://review.couchbase.org/40835
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>