fix: silverware node_util tries extra hard to get the cloud-assigned private hostname when asked for a private hostname

Squashed commit of the following:

commit 96c38f980ef4d8693ee0dc1ec2221b455f4ccbf8
Author: Chris Howe <howech@infochimps.com>
Date:   Tue Apr 1 10:35:19 2014 -0500

    Made the private_hostname try to look for the cloud-private hostname.

Change-Id: I00ef3f35caf2573911718c2f4f26aca36b284ff8