removing folders which are not in mailboxes.db

[Marcus Schopen]

some more info:

I did some further checks:

those messages are not shown by unexpunge -l. I get a "Failed to open
mailbox" if I check the delete subdirs, which is correct to my mind,
because these mailbox don't exist any more. 

The delete subdirs didn't show up in DELETED.user. I use "delete_mode:
delayed" and "expunge_mode: delayed" and did a "expire -E 1 -X 0 -D 0 -v
-p DELETED.user.mailboxname" to remove all deleted mailbox, just to be
sure.

Ciao
Marcus