https://ce8i5.arvadosapi.com/users/sign_out path not found
When using Controller's native Google login, logging out results in an error.
Controller needs a Logout() method that bypasses railsProxy when Login.GoogleClientID is configured, similar to Login() in source:lib/controller/localdb/conn.go. The native implementation doesn't set cookies so I think this is a no-op, just redirecting to the return_to param value (or if none provided, workbench2?).