Added missing default TIME_ZONE in default.settings.py.
Added missing default TIME_ZONE in default.settings.py.

CatoTH/OpenSlides,ostcar/OpenSlides,jwinzer/OpenSlides,OpenSlides/OpenSlides,FinnStutzenstein/OpenSlides,normanjaeckel/OpenSlides,tsiegleauq/OpenSlides,emanuelschuetze/OpenSlides,jwinzer/OpenSlides,emanuelschuetze/OpenSlides,FinnStutzenstein/OpenSlides,CatoTH/OpenSlides,normanjaeckel/OpenSlides,jwinzer/OpenSlides,emanuelschuetze/OpenSlides,boehlke/OpenSlides,boehlke/OpenSlides,boehlke/OpenSlides,emanuelschuetze/OpenSlides,rolandgeider/OpenSlides,CatoTH/OpenSlides,FinnStutzenstein/OpenSlides,tsiegleauq/OpenSlides,FinnStutzenstein/OpenSlides,tsiegleauq/OpenSlides,jwinzer/OpenSlides,CatoTH/OpenSlides,OpenSlides/OpenSlides,ostcar/OpenSlides,normanjaeckel/OpenSlides,ostcar/OpenSlides,normanjaeckel/OpenSlides,boehlke/OpenSlides,rolandgeider/OpenSlides,jwinzer/OpenSlides,rolandgeider/OpenSlides