A key made by mistake on a server that is being restored left no way back: key:import and the
passphrase route refused because a key existed, and nothing removed it. As long as the key never
protected anything (no location created or adopted with it, no location or run in the database),
occ backup:key:import --replace-unused-key and occ backup:target:add --replace-unused-key replace
it, after the new key was opened. A key that was used is never replaced, also after its location
was removed. The refusal names the option, and all administrators are notified of a replacement.
On a server without a backup key, backup:target:add finds the backups at
the location and takes their key from its config with one of the old
server's passphrases. Backups then wait until a new recovery kit is
confirmed. The deletion delay and the repository id are now stored on the
location, sealed with the key, so the delay survives a restore without a
kit and --repair-config can write a lost config again from the kit.
The key page warns against creating a new key when restoring a server.
New test: tests/integration/recovery-scenarios.sh, and a no-kit mode in
full-restore-roundtrip.sh.
dillard