add-model fails erroneously when a cloud is specified and a credential is specified and needs to be uploaded.

[Martin Hilton]

if you try to add a model using a command like:

juju add-model --credential cred test-model google/europe-west1

Then this results in the error message:

ERROR region "google/europe-west1" not found (expected one of ["asia-east1" "europe-west1" "us-central1" "us-east1"])

Some digging around shows that this correctly resolves the region the first time, but it tries to do it again when retrieving the credential from local storage to upload it to the controller. At this point it uses the originally specified region and finds it doesn't match any of the regions valid for the cloud.

For reference the error details are:

(error details: [{github.com/juju/juju/cmd/juju/controller/addmodel.go:201: } {github.com/juju/juju/cmd/juju/controller/addmodel.go:437: } {github.com/juju/juju/cmd/modelcmd/credentials.go:76: } {github.com/juju/juju/cloud/clouds.go:224: region "google/europe-west1" not found (expected one of ["asia-east1" "europe-west1" "us-central1" "us-east1"])}])

[Horacio Durán (hduran-8)]

I proposed https://github.com/juju/juju/pull/6300