Remove unused import.

quotaholder/servers/django_backend/callpoint.py

@@ -6,7 +6,7 @@ from quotaholder.api import (
 
 from commissioning import Callpoint, CorruptedError, InvalidDataError
 from commissioning.utils.newname import newname
-from django.db.models import Model, BigIntegerField, CharField, ForeignKey, Q
+from django.db.models import Q
 from django.db import transaction, IntegrityError
 from .models import (Holder, Entity, Policy, Holding,
                      Commission, Provision, ProvisionLog, now)