Use a default all scopes to create credentials.

Seperate scopes for each api call will ask user to go oauth2 flow
multiple times.This cl try to use a default all scopes to create
credential and reuse it for all cloud api call.

Bug: 118287079
Test: rm ~/.acloud_oauth2.dat &&
run acloud create/delete cmd only see oauth2 flow once
atest acloud_test

Change-Id: Ie8a204c8825b82e300a5f5e4dba548658dc8a45f
9 files changed