Comment 6 for bug 1868326

So the bug in the series-upgrade is due to the 'resume' action (which restarts the mysql service) syncing data over the directory and wiping out the seeded file. I've put in a 'rescue' for the series-upgrade to ensure that if the seeded file is there prior to the restart, then it is placed back after the restart to ensure continued operation of the charm.

Review: https://review.opendev.org/#/c/749922