Minor fix in disco.core: Check the number of input files *after* dir:// expansion
Minor fix in disco.core: Check the number of input files *after* dir:// expansion

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