Commit ee5d4942a1c33736ffe05ec01619142be400c2f4 changed the existing
behavior so that if an ipmitool command fails when attempting to set
the power state it causes a failure. The problem with that approach
is that on some systems if the system is already in the desired power
state, an error will be generated when ipmitool tries to change it to
the desired power state.
Now when doing a reboot command we check beforehand to see if the node
is already off, if so then don't attempt to power off the node again.
Also optimize ironic/conductor/utils.py node_power_action() so that it
only checks a node's power status if it might perform an action based
on the node's power status.
Change-Id: If838aae871753ebfbdf359e0bbe3afcc54c4b559
Closes-Bug: #1718794
8ceaad42ff