Attaching a file after a rollback restores previous attachments

Follow this steps to reproduce:

• create a new plain wiki page (version 1.1)
• attach a file (version 2.1)
• rollback to version 1.1 (version 3.1 is created with no attachments listed)
• attach a different file (version 4.1)

The last version, 4.1, lists both attachments.