More adjustments

- Use the generated_by() utility function to
  give the ruby template a better header comment
- Set special parameters after selecting the basic
  chef parameters.

templates/chef_client.rb.tmpl

@@ -9,12 +9,11 @@ you need to add the following to config:
     validation_name: XYZ
     server_url: XYZ
 -#}
-
+{{generated_by}}
 {#
 The reason these are not in quotes is because they are ruby
 symbols that will be placed inside here, and not actual strings...
 #}
-# This is a generated file, created on {{generated_on}}.
 {% if log_level %}
 log_level              {{log_level}}
 {% endif %}