Picasa repository not fully removed by MDL-58939

When the picasa repository was removed in MDL-58939 it didn't fully remove the plugins configuration, meaning every time there's a version bump on the site, I'm prompted to uninstall the plugin again - but it never appears to succeed:

We should remove the correct configuration here: https://github.com/moodle/moodle/blob/214adb798498741f9ddfe3533efcb106db8ad6ec/lib/db/upgrade.php#L2826-L2827 ('repository_picasa')

The testing instructions on MDL-58939 have the step:

Check the following SQL query is not empty: 

SELECT * FROM mdl_config_plugins WHERE plugin = 'picasa'

But that plugin doesn't exist, nor appear to return any records on current 311_STABLE branch, which is a bit confusing