* When deleting a lan can there is only one interface left, need to go
  back and delete the interface from the last node. Else its a malformed
  rpsec (which we have been ignoring), but it was passing through to the
  manifest, which made it a malformed manifest.

* But a later bug was causing that now removed interface to sneak back
  in via the old copy of the manifest in the database.

* Also fix a bug that was causing multiple versions of the site_info
  element to get inserted during an update.

* Remove code that updates the manifest in the DB, use the existing
  Aggregate->UpdateManifest() method instead.