Groups portal Google Analytics code

Add optional GA tracking code variable to settings.php template and add
tracking code to groups.openstack.org site.

Change-Id: Iddf223cab9ef672178f4e2984cdacf27a8d0f16f

manifests/init.pp

@@ -70,6 +70,7 @@ class drupal (
   $package_branch = undef,
   $conf_cron_key = undef,
   $conf_markdown_directory = undef,
+  $conf_ga_account = undef,
 ) {
   include apache
   include pear

templates/settings.php.erb

@@ -12,3 +12,6 @@ $conf['cron_key'] = '<%= @conf_cron_key %>';
 <% if @conf_markdown_directory %>
 $conf['groups_feeds_markdown_directory'] = '<%= @conf_markdown_directory %>';
 <% end %>
+<% if @conf_ga_account %>
+$conf['googleanalytics_account'] = '<%= @conf_ga_account %>';
+<% end %>