Valid values are OK, WARNING, ERROR

I will file a bug to fix the doc.

Note, I think the best practice here is to actually not set the status with
the CompleteBuildTask. But, instead, to set status with the
LogPublisherTask.

For example, if you set status="ERROR" on the LogPublisherTask, publishing a
log file that explains why the build failed (create a temporary one if you
have to). Then that log will show up on the Logs tab of the build result
with a little red x decoration, and the overall build status will be ERROR
(the overall status is always the most severe of the contributed status).

The decoration helps the user see why the build failed.

If you just use CompleteBuildTask, the overall build can be ERROR, but the
user may have no idea why or where to look.

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Ryan Manwiller
Jazz Team