failing update Smart Groups for installs with none

I got past an upgrade error by commenting out lines 96 through 118 in CRM/Upgrade/Incremental/php/FiveTwenty.php

The the update was repeatedly failing on this install which had no smart groups, had never had smart groups, and was probably five years old or more. I have no idea how to reproduce the issue reliably but if there isn't already a failsafe in the code for installs which have no smart groups to update, please add that failsafe.

Peace out!