gcloud._helpers._compute_engine_id should return a str (Python 3)

[flunderpero]

I stumbled upon this while deploying my app for the first time on GKE/GCE.

I had to explicitly specify project when creating a client: gcloud.datastore.Client(project="my-project"), otherwise I just got an gcloud.exceptions.ServiceUnavailable: 503 Backend Error.

First I thought the problem would be that autodetecting the project-id didn't work, but gcloud.datastore.Client(credentials=credentials, project=project) returns my project-id, be it as bytes instead of str.

I quickly verified that using bytes as a project-id does not work, i.e. gcloud.datastore.Client(project=b"my-project") resulted in that neat 503 Backend Error.

[pcostell]

Moved over to gcloud-python.