Corrected omitted variable

netbox/dcim/views.py

@@ -15,7 +15,7 @@ from django.views.generic import View
 
 from ipam.models import Prefix, IPAddress, VLAN
 from circuits.models import Circuit
-from extras.models import Graph, TopologyMap, GRAPH_TYPE_INTERFACE
+from extras.models import Graph, TopologyMap, GRAPH_TYPE_INTERFACE, GRAPH_TYPE_SITE
 from utilities.forms import ConfirmationForm
 from utilities.views import (
     BulkDeleteView, BulkEditView, BulkImportView, ObjectDeleteView, ObjectEditView, ObjectListView,