client: ignore a client timeout, if the last thing we saw as a trigger

client: ignore a client timeout, if the last thing we saw as a trigger

If triggers are used and are fatal to the fio backend (killing power,
etc), then we don't have time to process the stop/quit commands. We
expect the client to go away, but the backend can't let us know.

If the last thing we saw was a trigger command, don't exit in error
if the client times out and goes away.

Signed-off-by: Jens Axboe <axboe@kernel.dk>