[FIXED] Wrong pickle returned adding interval
[FIXED] Wrong pickle returned adding interval

In session timetable, we were returning the pickle of the conference
schedule instead of the session schedule.

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