[1.6.x] Updated timezone docs to use timezone.now()
[1.6.x] Updated timezone docs to use timezone.now()

Thanks James Cleveland for the report and Aymeric for suggesting
the solution.

Backport of da59902250 from master

felixjimenez/django,felixjimenez/django,felixjimenez/django,redhat-openstack/django,django-nonrel/django,django-nonrel/django,django-nonrel/django,felixjimenez/django,redhat-openstack/django,django-nonrel/django,redhat-openstack/django,redhat-openstack/django