Update CDN link for bootstrap css
Update CDN link for bootstrap css

gwasser/django-helpdesk,django-helpdesk/django-helpdesk,gwasser/django-helpdesk,gwasser/django-helpdesk,django-helpdesk/django-helpdesk,django-helpdesk/django-helpdesk,django-helpdesk/django-helpdesk,gwasser/django-helpdesk