ZNC 1.4 uses a new section within the configuration file to specify
password hash and salt. This requires adding a new Ansible variable
'irc_password_salt'.

Also update the README file to reflect above changes.

Also see: http://b.wardje.eu/2011/12/znc-failing-to-connect.html

To bring this certificate in line with how those in ssl.yml are managed.

This URL works for all releases, not just the latest one.

Refs #39

Fix CAcert usage in postfix and dovecot