Returns a 404 when querying status of queued build

[Graham Davison]

When a build is queued, running tctest status returns a 404 error, rather than reporting a queued status.

Expected behaviour:

$ tctest status 1234
Build queued

Actual behaviour:

$ tctest status 1234
ERRO[2019-11-27 15:34:52] tctest: HTTP status NOT OK: 404