Have all tag code add, modify and delete both old and new style tags

This preps us for being able to use the new data model with existing repositories

workers/test/test_manifestbackfillworker.py

@@ -2,7 +2,7 @@ from app import docker_v2_signing_key
 from data import model
 from data.database import (TagManifestLabelMap, TagManifestToManifest, Manifest, ManifestBlob,
                            ManifestLegacyImage, ManifestLabel, TagManifest, RepositoryTag, Image,
-                           TagManifestLabel)
+                           TagManifestLabel, Tag, TagToRepositoryTag)
 from image.docker.schema1 import DockerSchema1ManifestBuilder
 from workers.manifestbackfillworker import backfill_manifest
 from workers.labelbackfillworker import backfill_label
@@ -12,6 +12,8 @@ from test.fixtures import *
 @pytest.fixture()
 def clear_rows(initialized_db):
   # Remove all new-style rows so we can backfill.
+  TagToRepositoryTag.delete().execute()
+  Tag.delete().execute()
   TagManifestLabelMap.delete().execute()
   ManifestLabel.delete().execute()
   ManifestBlob.delete().execute()