Remove the duplicate target power state and last error check&update

[Kan]

There is a target power state and last error check and update when changing
node power state, while there is also a target power state and last error check
and update in its following code flow, which is duplicated. They will also be
updated when an error happens before 'node_power_action' is really called in
'power_state_error_handler' hook function.
Will remove the previous one to make the check and update happen in one place.

The previous target power state and last error check&update:
https://github.com/openstack/ironic/blob/master/ironic/conductor/manager.py#L257

The following target power state and last error check&update in right logic:
https://github.com/openstack/ironic/blob/master/ironic/conductor/utils.py#L76
https://github.com/openstack/ironic/blob/master/ironic/conductor/utils.py#L117

The following target power state and last error check&update in error handler hook function:
https://github.com/openstack/ironic/blob/master/ironic/conductor/utils.py#L230

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/264527

[Ruby Loo (rloo)]

I don't think this is a bug. We set the node.target_power_state before we spawn a worker to do the work, in case some error happens before utils.node_power_action() makes the change.

[Kan (kansks)]

Thanks for your comment, Ruby. As I commented in the review patch,
the 'power_state_error_handler' hook function will update the target
power state to NOSTATE instead of maintaining the previous target
power state. And for the right logic, 'node_power_action' will take care
the situation. These ensure the target power state can be set a fully
readable record for the users, so I think there is no need to reset it
before spawn a worker. WDYT?

[OpenStack Infra (hudson-openstack)]

Change abandoned by Ruby Loo (<email address hidden>) on branch: master
Review: https://review.openstack.org/264527
Reason: Abandoning because nothing has happened since 2016 and for the reasons why I -2'd it.

[Iury Gregory Melo Ferreira (iurygregory)]

Marking as invalid due to the inactivity, feel free to reopen if necessary.