Update to Dovecot 2.1.4.

+ Added mail_temp_scan_interval setting and changed its default value
  from 8 hours to 1 week.
+ Added pop3-migration plugin for easily doing a transparent IMAP+POP3
  migration to Dovecot: http://wiki2.dovecot.org/Migration/Dsync
+ doveadm user: Added -m parameter to show some of the mail settings.
- Proxying SSL connections crashed in v2.1.[23]
- fts-solr: Indexing mail bodies was broken.
- director: Several changes to significantly improve error handling
- doveadm import didn't import messages' flags
- mail_full_filesystem_access=yes was broken
- Make sure IMAP clients can't create directories when accessing
  nonexistent users' mailboxes via shared namespace.
- Dovecot auth clients authenticating via TCP socket could have failed
  with bogus "PID already in use" errors.

(ghen)