If mailbox is deleted under us while we're also deleting it, handle it without logging an error message.
If mailbox is deleted under us while we're also deleting it, handle it
without logging an error message.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot