CCBC-433 A new randomization algorithm.

Now using a Fisher–Yates shuffle to randomize the host list.

Change-Id: I03ccffdaedfcfe52f5fbddb367657fc8e0c76074
Reviewed-on: http://review.couchbase.org/37706
Reviewed-by: Dave Rigby <daver@couchbase.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>