m-c-s debinstall script breaks because curtin_userdata can't be found

[Jeff Lane ]

Since maas has moved to a snap for Focal and MAAS 2.7, the debinst script for maas-cert-server breaks while trying to find curtin_userdata in /etc/maas.

these now exist in /snap/maas/current/etc/maas/preseeds/

According to discourse, the following is the solution for the snap:

In the snap, you can override existing preseeds by putting a different version of the file (matching the original name in /var/snap/maas/current/preseeds/.
The directory will contain *.sample files that are a copy of the original ones.
You can copy/rename the one(s) you want to override and make the necessary changes. They will take precedence over the ones shipped in the snap.
https://discourse.maas.io/t/how-to-create-customs-curtin-userdata-when-maas-runs-in-snap/1363