dispatch_runner: migrate to using poll()
dispatch_runner: migrate to using poll()

There's no real benefit here, but it seems to cleanup the code a bit.

piotr1212/carbon-c-relay,piotr1212/carbon-c-relay,piotr1212/carbon-c-relay,piotr1212/carbon-c-relay,grobian/carbon-c-relay,grobian/carbon-c-relay,grobian/carbon-c-relay