v2.0.0 reads the config strictly and stops at the v1 keys the addon
wrote (server.port, conditionals, indexingIntervalMinutes). It also only
imports the old BoltDB when server.database.migrateFrom names it and no
database.db is left in the working directory. The update now rewrites
the config, renames the database and points migrateFrom at it, keeping
a copy of the v1 config. New installs write the v2 layout.