[Dovecot] Stop Maildir appending to path

[Henry]

dovecot -n:
# /etc/dovecot/dovecot.conf
log_timestamp: %Y-%m-%d %H:%M:%S
protocols: imaps
ssl_listen: 208.xxx.xxx.xxx
login_dir: /var/run/dovecot/login
login_executable: /usr/lib/dovecot/imap-login
mail_extra_groups: mail
mail_debug: yes
auth default:
  passdb:
    driver: pam
  passdb:
    driver: sql
    args: /etc/dovecot/dovecot-sql.conf
  userdb:
    driver: passwd
  userdb:
    driver: static
    args: uid=5000 gid=5000 home=/home/vmail/%d/%n allow_all_users=yes
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
    master:
      path: /var/run/dovecot/auth-master
      mode: 384
      user: vmail
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dovecot version: 1.0.rc15

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Debian Etch (Stable) on AMD64