The change in 7a7357dae1bcccb17e9b2d4c7c8f5c025fce56ca inadvertently changed the `defer` error code into a no-op. This restores its behavior prior to that code change, and also introduces a little more error logging. Signed-off-by: Euan Kemp <euan.kemp@coreos.com> Upstream-commit: 639ab92f011245e17e9a293455a8dae1eb034022 Component: engine