Validate the power interface before deployment

This patch makes the do_node_deploy() validate the drivers power interface
before start deploying a node because powering the node on/off is part
of the deployment.

Change-Id: Ic52c49ac6c8631f81eb50b69a5bdb56a113a72b4
Closes-Bug: #1378301
Merge "Validate the power interface before deployment"