cleaner removed items from config_log breaking future upgrades

[dustinbrisebois]

After running data cleaner we attempted to run major upgrades to the LMS (from 3.1 to 3.5) we found that the default settings had removed unused plugin default settings from config_log - which stores all plugin configuration defaults.

As the upgrader checks these defaults when it runs it failed as the settings didn't exist anymore (even if they aren't in use). To recover the upgrade we had to import the last known copy of the config_log table.