dovecot: bump version to 2.2.29.1 (security)

dovecot: bump version to 2.2.29.1 (security)

Security fix:

  passdb/userdb dict: Don't double-expand %variables in keys. If dict
  was used as the authentication passdb, using specially crafted
  %variables in the username could be used to cause DoS (CVE-2017-2669)

Full ChangeLog 2.2.29 (including CVE fix):
  https://www.dovecot.org/list/dovecot-news/2017-April/000341.html

Full ChangeLog 2.2.29.1 (some fixes forgotten in the 2.2.29 release):

  https://www.dovecot.org/list/dovecot-news/2017-April/000344.html

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>