Fix error with non-postgresql sqlalchemy errors
Fix error with non-postgresql sqlalchemy errors

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