Add correct self-link

The self-link was missing the resource id, properly add the id to
the self-link now.

Change-Id: I82c59fc3a02e4182147ec8090d54cfe82b8d0c61
Partial-Bug: #1776504

keystone/server/flask/common.py

@@ -528,7 +528,7 @@ class ResourceBase(flask_restful.Resource):
 
     @classmethod
     def _add_self_referential_link(cls, ref):
-        self_link = '/'.join([base_url(), 'v3', cls.collection_key])
+        self_link = '/'.join([base_url(), 'v3', cls.collection_key, ref['id']])
         ref.setdefault('links', {})['self'] = self_link
 
     @classmethod

keystone/tests/unit/server/test_keystone_flask.py

@@ -77,6 +77,8 @@ class _TestResourceWithCollectionInfo(flask_common.ResourceBase):
             raise exception.NotFound(target=argument_id)
         ref = flask.request.get_json(force=True)
         self._require_matching_id(ref)
+        # Maintain the ref id
+        ref['id'] = argument_id
         self._storage_dict[argument_id] = ref
         return '', 204