Fix "501 Syntax error in parameters" from yahoo

As recommended by:

  http://www.businesscorner.co.uk/postfix-mail-yahoo-com-said-501-syntax-error-in-parameters-or-arguments-in-reply-to-mail-from-command
Fix fqdn and domain in attributes

From pull request https://github.com/opscode-cookbooks/postfix/pull/4/files