Fix room bookable hours containing 00:00
Fix room bookable hours containing 00:00

fixes #1755

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