[1.8.x] Removed unused import in example code in docs/topics/auth/default.txt
[1.8.x] Removed unused import in example code in docs/topics/auth/default.txt

Backport of 10945ebeb84157a284ad96f453ee13305a9d8a94 from master

h4r5h1t/django-hauthy,pquentin/django,pquentin/django,h4r5h1t/django-hauthy,pquentin/django,h4r5h1t/django-hauthy,h4r5h1t/django-hauthy