mailboxes.db discrepancies between mailbox and mupdate servers

[Shawn Winnington-Ball]

> According to my notes, MUPDATEPUSH is used through an admin user's IMAP connection (via imtest) not through mupdatetest.
> 
> If the mailbox doesn't actually exist, you might need to use LOCALCREATE via IMAP to the backend prior to MUPDATEPUSH.
> 
> LC1 LOCALCREATE user.foo

Thank you Simon, this did the trick to recreate the directory
structure on-disk and populate the mailboxes.db file on the backend.

Shawn