Merge "Revert "Use HasStandardAttributes as parent class for Tags DB model"" into unmaintained/yoga

Author: Zuul

neutron/db/models/tag.py

@@ -26,6 +26,6 @@ class Tag(model_base.BASEV2):
     tag = sa.Column(sa.String(255), nullable=False, primary_key=True)
     standard_attr = orm.relationship(
         'StandardAttribute', load_on_pending=True,
-        backref=orm.backref('tags', lazy='joined', viewonly=True),
+        backref=orm.backref('tags', lazy='subquery', viewonly=True),
         sync_backref=False)
     revises_on_change = ('standard_attr', )