[1.6.x] Fixed #19489 -- Documented host parameter of assertRedirects().
[1.6.x] Fixed #19489 -- Documented host parameter of assertRedirects().

Thanks mrknacky at gmail.com for the report and gajimenezmaggiora
for the draft patch.

Backport of e3c7af18a3 from master

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