openid: Fix a warning on Python 3.x
openid: Fix a warning on Python 3.x

pztrick/django-allauth,joshowen/django-allauth,bittner/django-allauth,rsalmaso/django-allauth,joshowen/django-allauth,lukeburden/django-allauth,bittner/django-allauth,AltSchool/django-allauth,pennersr/django-allauth,lukeburden/django-allauth,pztrick/django-allauth,rsalmaso/django-allauth,pennersr/django-allauth,joshowen/django-allauth,pztrick/django-allauth,AltSchool/django-allauth,AltSchool/django-allauth,lukeburden/django-allauth,rsalmaso/django-allauth,pennersr/django-allauth,bittner/django-allauth