idp_oidc: remove unused import

src/authentic2_idp_oidc/views.py

@@ -10,7 +10,6 @@ from django.utils.http import urlencode
 from django.shortcuts import render
 from django.views.decorators.csrf import csrf_exempt
 from django.core.urlresolvers import reverse
-from django.contrib.auth import REDIRECT_FIELD_NAME
 from django.contrib import messages
 from django.conf import settings
 from django.utils.translation import ugettext as _