Fix delete zone transfer request with scoped token

This patch fixes an issue were deleting a zone transfer request with a scoped
token may fail.

Change-Id: I4522796ac056630c63798830e8f8d92628f14a37

designate/storage/impl_sqlalchemy/__init__.py

@@ -1490,6 +1490,8 @@ class SQLAlchemyStorage(sqlalchemy_base.SQLAlchemy, storage_base.Storage):
             # all_tenants was not used, we don't know what records to return,
             # so return an empty list.
             if not context.project_id:
+                if one:
+                    return objects.ZoneTransferRequest()
                 return objects.ZoneTransferRequestList()
 
             query = query.where(or_(

releasenotes/notes/fix-zone-transfer-request-scoped-token-fc9d3be407e1a50a.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixed a bug where deleting a zone transfer request may fail when using
+    a system scoped token.