* Don't delete old db after migration
Fixes unwanted shuffling&deletion of the old database after a
migration that merely deletes data in one of the existing database
columns.
* Update util/migration-rocksdb/src/lib.rs
Co-Authored-By: Andronik Ordian <write@reusable.software>
Co-authored-by: Andronik Ordian <write@reusable.software>