remove unused import

Author: ohmayr

packages/django-google-spanner/tests/system/django_spanner/test_check_constraint.py

@@ -11,7 +11,6 @@
 from django.db.utils import IntegrityError
 from django.test import TransactionTestCase
 from django.utils import timezone
-from google.api_core.exceptions import OutOfRange
 
 from django_spanner import USE_EMULATOR
 from tests.system.django_spanner.utils import (