fixed a broken screenshot link in install.rst (thanks to traviscline)
fixed a broken screenshot link in install.rst (thanks to traviscline)

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