Android p preview 5
Update oauth2client credential API call.

The previous version of acloud was using oauth2client 1.4.12, but now
we've updated to 3.0.0 which deprecated the credential API we called
(oauth2client.client.SignedJwtAssertionCredentials) which is now switched to
the service_account module.

https://github.com/google/oauth2client/issues/401

Bug: 111319023
Test: ./run_tests.sh && m acloud && acloud create with a service acct.
Change-Id: Id01be26e3646c82ba92402076f3f6b18afe7cfd9
1 file changed