newconfig: Only initiate connections to nodes that have commands

We don't need to connect to all the nodes (making logging messages quite
noisy). Only connect to those nodes that have commands waiting on them.

Change-Id: I24a4b3a5ec8cfab57310dd5b8abc767e13a6453b
Reviewed-on: http://review.couchbase.org/39832
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>