Force django-celery version in travis
Force django-celery version in travis

ioannisstenos/e-science,ibyron/e-science,KPetsas/e-science,ioannisstenos/e-science,ioannisstenos/e-science,grnet/e-science,grnet/e-science,ibyron/e-science,grnet/e-science,ibyron/e-science,KPetsas/e-science,ioannisstenos/e-science,KPetsas/e-science,KPetsas/e-science,ioannisstenos/e-science,ibyron/e-science,grnet/e-science,grnet/e-science,KPetsas/e-science,ibyron/e-science