[1.6.x] Fixed typo in docs/ref/request-response.txt.
[1.6.x] Fixed typo in docs/ref/request-response.txt.

Backport of 49d034fff21213b369c08b39772e0437c3cc723b from master

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