Migration 0005 (MigrateNFSClients) only runs once when first applied,
so any fsid=0 rows present before 0005 was applied never get repaired.
Migration 0006 triggers FixZeroFSIDs() which:
- Queries all nfs_exports rows with fsid=0
- Generates a new random fsid per row
- Updates the row
Version: 0.5.2
