fix redirection of async endpoints response codes from "202 - Accepted" to "303 - See other"

[milan k]

Currently, there are /v1/controllers/node/ endpoints that both set a location header and a status code 202 - Accepted in the response.
According to the RFC[1][2], this shouldn't be the case unless a resource was created by the original request.
Please correct this to a "303 - See Other"[3] response code or avoid using the location header.

It seems the endpoints affected are (in terms of source code):
ironic/api/controllers/v1/node.py:
 NodeConsoleController.put
 NodeStatesController.power
 NodeStatesController.provision

[1] https://tools.ietf.org/html/rfc7231#section-7.1.2
[2] https://en.wikipedia.org/wiki/HTTP_location
[3] https://en.wikipedia.org/wiki/HTTP_303

[Dmitry Tantsur (divius)]

That's pretty arguable (as I already mentioned offline), as there seems to be enough places even in RFC's where 202+location are used. Also 202 requires some reference to actual results, which seems a perfect use case for the location header to me. Anyway, pleae feel free to bring this question to a wider discussion on the ML or the team meeting.