[FIX] Do not link a conference with no id attr
[FIX] Do not link a conference with no id attr

DirkHoffmann/indico,mvidalgarcia/indico,OmeGak/indico,ThiefMaster/indico,DirkHoffmann/indico,indico/indico,mvidalgarcia/indico,indico/indico,pferreir/indico,DirkHoffmann/indico,mvidalgarcia/indico,mic4ael/indico,mic4ael/indico,mvidalgarcia/indico,ThiefMaster/indico,ThiefMaster/indico,OmeGak/indico,pferreir/indico,indico/indico,pferreir/indico,OmeGak/indico,DirkHoffmann/indico,ThiefMaster/indico,mic4ael/indico,indico/indico,OmeGak/indico,mic4ael/indico,pferreir/indico