Fix system tests when running on GCE

The new project ID logic for Cloud SDK invokes Cloud SDK directly. Cloud SDK helpfully falls back to the GCE project ID if the project ID is unset in the configuration. This breaks one of our previous expectations.

Author: Jon Wayne Parrott

system_tests/test_default.py

@@ -24,7 +24,5 @@ def test_application_default_credentials(verify_refresh):
 
     if EXPECT_PROJECT_ID is not None:
         assert project_id is not None
-    else:
-        assert project_id is None
 
     verify_refresh(credentials)