[1.5.x] Correct very minor typo
[1.5.x] Correct very minor typo

Just changed as to has.

Backport of d8f2d940cc from master

ccn-2m/django,bliti/django-nonrel-1.5,ccn-2m/django,bliti/django-nonrel-1.5,ccn-2m/django,bliti/django-nonrel-1.5,ccn-2m/django