Comment 7 for bug 1663458

I checked whether other services expose similar behavior in regards to postponing shutdown until backoff timeout is up. I was hoping that by using oslo.service and relying on its signal handlers, we could avoid waiting for so long to shut down a service. Sadly, it doesn't seem to be the case: L3 agent that already uses oslo.service library still hangs for 480 secs after signal received to exit.