MINOR: stream: Add level 7 retries on http error 401, 403

MINOR: stream: Add level 7 retries on http error 401, 403

Level-7 retries are only possible with a restricted number of HTTP
return codes. While it is usually not safe to retry on 401 and 403, I
came up with an authentication backend which was not synchronizing
authentication of users. While not perfect, being allowed to also retry
on those return codes is really helpful and acts as a hotfix until we
can fix the backend.

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>