Add ability to see ip_policy_id on subnet response

RM10550

quark/api/extensions/subnets_quark.py

@@ -20,6 +20,8 @@ from neutron.api import extensions
 EXTENDED_ATTRIBUTES_2_0 = {
     "subnets": {
         "segment_id": {"allow_post": True, "default": None},
+        "ip_policy_id": {"allow_post": False, "allow_put": False,
+                         "default": None, "is_visible": True}
     }
 }