spec: fix mysql when models don't have tables

Change-Id: I6d4e7c314d4bce58c28dff659c1a498b40cea40a
Reviewed-on: https://gerrit.instructure.com/32064
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Bryan Madsen <bryan@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>