Need arbitrary stream names for testing

We are unable to test master because of the recent change that makes juju use devel streams when the version is not dotted-numbers. We cannot make a testing stream that has all the versions under test. We set agent-stream: "released" in the config, but juju still looked for "devel". Since we ask users to make test streams for their private clouds, they will likely also fail because they don't know that they must force "--stream devel" when calling generate-tools.

I suspect a bug in Juju. I tried "--agent-stream testing" knowing it would fail, I wanted to see Juju try to use an arbitrary stream name. I see this:
    agent-metadata-url: http://juju-dist.s3.amazonaws.com/testing/tools.
    2015-08-13 17:12:35 ERROR juju.cmd supercommand.go:429 agent-stream: expected one of [released devel proposed], got "testing"

The testing tree never head a devel or proposed stream. We can see at
    http://juju-dist.s3.amazonaws.com/testing/tools/streams/v1/index2.json
that only "released" is supported. Where did "proposed" come from?

Using "testing" stream the "testing" tree might not work. We could try. If it works, then we know Juju is a liar.

Juju QA, like other enterprise customers are going to create streams with mixed versions to test the interaction. the agent-stream must be honoured so that we can setup a test.