Change the security scan update query to only change the indexed row

This will mean we try to re-index other similar rows, but that's a no-op on the Clair side, and this update query is extremely heavy and easily interleaving locks

data/model/image.py

@@ -463,19 +463,9 @@ def get_image_with_storage_and_parent_base():
 
 
 def set_secscan_status(image, indexed, version):
-  query = (Image
-           .select()
-           .join(ImageStorage)
-           .where(Image.docker_image_id == image.docker_image_id,
-                  ImageStorage.uuid == image.storage.uuid))
-
-  ids_to_update = [row.id for row in query]
-  if not ids_to_update:
-    return False
-
   return (Image
           .update(security_indexed=indexed, security_indexed_engine=version)
-          .where(Image.id << ids_to_update)
+          .where(Image.id == image.id)
           .where((Image.security_indexed_engine != version) | (Image.security_indexed != indexed))
           .execute()) != 0