Resolve some warnings in the test suite

src/pretix/control/permissions.py

@@ -1,7 +1,8 @@
+from urllib.parse import quote
+
 from django.core.exceptions import PermissionDenied
 from django.shortcuts import redirect
 from django.urls import reverse
-from django.utils.http import urlquote
 from django.utils.translation import ugettext as _
 
 
@@ -93,7 +94,7 @@ def administrator_permission_required():
                 raise PermissionDenied()
             if not request.user.has_active_staff_session(request.session.session_key):
                 if request.user.is_staff:
-                    return redirect(reverse('control:user.sudo') + '?next=' + urlquote(request.path))
+                    return redirect(reverse('control:user.sudo') + '?next=' + quote(request.path))
                 raise PermissionDenied(_('You do not have permission to view this content.'))
             return function(request, *args, **kw)
         return wrapper