Correct substring matching of baremetal VPD node names

This path corrects a issue where is_power_on function can incorrectly match a
node if its name is a substring of another node.

I have also added a test for this.

fixes bug 1152676
Change-Id: Ic3b0b952d53dcd4464098f98879a84684efe22b2
Authored-by: Chris Krelle <nobodycam@gmail.com>
Merge "Correct substring matching of baremetal VPD node names"