This applies only to source based installations.
The introduction of smart-sources in [1] created a code path
which deletes the /etc/keystone directory before symlinking it
into the keystone venv and creating the necessary config files.
Unfortunatley this has the side effect of also deleting any fernet
and credential keys which pre-existed in the case of an upgrade from
Rocky. The original keys were deleted simulataneously across the whole
keystone_all group in a way which is makes them unrecoverable in
the absence of a backup taken by the operator.
This change simplifies the smart-sources code to always keep the
keystone config files and fernet keys in the host /etc/keystone.
This ensures that the lifecycle of the fernet keys is not coupled
to the lifecycle of the keystone venvs.
In addition, a task is added to rescue any keys which have been
created in the keystone venv by installations from the Stein
release-candidate.
[1] https://review.opendev.org/#/c/588960/
Closes-Bug: 1833414
Change-Id: Ide611fd3d88e352367220f05dbcf4186ac20319f
8e1f7f4ad8