Migrate SignedJwtAssertionCredentials to ServiceAccountCredentials

[Zenahr]

Explanation:
SignedJwtAssertionCredentials was removed from the oath2client python package in the 2.0.0 update. It was no more under oauth2client.client. The behaviour has been moved onto oauth2client.service_account.ServiceAccountCredentials.

See this SO thread for more info.

Additional Notes

Developers need to perform following tasks on their dependencies in order for this to work:

pip install pyOpenSSL
pip install --upgrade oauth2client

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[Zenahr]

CLA signed.

[Zenahr]

@googlebot I signed it!

[Sebadst]

I think you forgot to actually use it. You are still using SignedJwtAssertionCredentials.

[Sebadst]

Also, oauth2client is deprecated now, so I would probably completely replace this sample with one using the Credentials from google.oauth2 instead.

NOTE: I am not part of the Google community, just sharing my opinion

[Zenahr]

I think you forgot to actually use it. You are still using SignedJwtAssertionCredentials.

You're right! I overlooked that.

Also, oauth2client is deprecated now, so I would probably completely replace this sample with one using the Credentials from google.oauth2 instead.

NOTE: I am not part of the Google community, just sharing my opinion

Yeah, I'll leave it open to Google and on how they decide to proceed with the samples. Good to have your comment here though for others to read.