Randomize supplied nodes list by default

Change-Id: Ie65c0e76fa8601d9df28652206149dc47cddd4be
Reviewed-on: http://review.couchbase.org/28890
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>