Fix the tests and implement a fake stripe.

endpoints/api/organization.py

@@ -1,8 +1,8 @@
 import logging
-import stripe
 
 from flask import request
 
+from app import billing as stripe
 from endpoints.api import (resource, nickname, ApiResource, validate_json_request, request_error,
                            related_user_resource, internal_only, Unauthorized, NotFound,
                            require_user_admin, log_action, show_if)
@@ -12,7 +12,7 @@ from auth.permissions import (AdministerOrganizationPermission,  OrganizationMem
                               CreateRepositoryPermission)
 from auth.auth_context import get_authenticated_user
 from data import model
-from data.plans import get_plan
+from data.billing import get_plan
 from util.gravatar import compute_hash
 
 import features