AZ607: A migration applied out of order

Each policy migration starts from the policy the one before it left, recorded in authz.policy_versions. This database is somewhere else: a migration was skipped, or the database was changed with rowfence push or apply since. Apply the migrations in order; a database changed by push takes the migrations from the start, or rowfence apply of the policy the previous migration left.

Reported when a policy migration runs.