worker: fix the input termination condition.
worker: fix the input termination condition.

Disco is done sending inputs to the worker when it sends the worker
the "done" message with the input.  Otherwise, the worker should
keep requesting inputs.

seabirdzh/disco,pombredanne/disco,discoproject/disco,pooya/disco,ErikDubbelboer/disco,discoproject/disco,pooya/disco,pombredanne/disco,pooya/disco,discoproject/disco,ErikDubbelboer/disco,ktkt2009/disco,ktkt2009/disco,mwilliams3/disco,seabirdzh/disco,beni55/disco,seabirdzh/disco,beni55/disco,beni55/disco,mozilla/disco,mozilla/disco,beni55/disco,pombredanne/disco,ktkt2009/disco,mwilliams3/disco,mwilliams3/disco,ErikDubbelboer/disco,simudream/disco,mozilla/disco,seabirdzh/disco,simudream/disco,mwilliams3/disco,oldmantaiter/disco,ktkt2009/disco,mwilliams3/disco,ErikDubbelboer/disco,oldmantaiter/disco,mozilla/disco,oldmantaiter/disco,simudream/disco,pombredanne/disco,simudream/disco,discoproject/disco,oldmantaiter/disco,beni55/disco,ktkt2009/disco,seabirdzh/disco,pooya/disco,pombredanne/disco,ErikDubbelboer/disco,simudream/disco,oldmantaiter/disco,discoproject/disco