Baremetal ensures node is off before powering on

During spawn(), ensure that a node is really off before trying to turn
it on. This fixes bug 1178919, in which a node that had previously
gotten stuck in a power-on state (eg, in the BIOS screen) would fail to
spawn() because the baremetal driver would send a power-on request, the
BMC would ignore it, and then baremetal driver would wait indefinitely
for a DHCP request.

Change-Id: Ie73e6ab488abe99c70ad3d149d702577941056d1
Merge "Baremetal ensures node is off before powering on"