Add VirtualHost to cacti vhost

It was missing the actual <VirtualHost> tag, which means that it
would lose out to the default vhost file that puppetlabs-apache
creates.  This may have behaved differently on apache2.2, but
it is certainly a problem on apache2.4 now that we have upgraded
to trusty.

Change-Id: I750ea9b8625d8d240616ce8306da81bcee832c95

manifests/site.pp

@@ -220,6 +220,7 @@ node 'cacti.openstack.org' {
   class { 'openstack_project::cacti':
     sysadmins   => hiera('sysadmins', []),
     cacti_hosts => hiera_array('cacti_hosts'),
+    vhost_name  => 'cacti.openstack.org',
   }
 }
 

modules/openstack_project/manifests/cacti.pp

@@ -2,6 +2,7 @@
 class openstack_project::cacti (
   $sysadmins = [],
   $cacti_hosts = [],
+  $vhost_name = '',
 ) {
 
   if $::osfamily != 'Debian' {

modules/openstack_project/templates/cacti.vhost.erb

@@ -2,6 +2,9 @@
 # Managed by Puppet
 # ************************************
 
+<VirtualHost *:80>
+  ServerName <%= @vhost_name %>
+
   Alias /cacti /usr/share/cacti/site
 
   RewriteEngine on
@@ -21,3 +24,4 @@ RewriteRule ^/$ /cacti/graph_view.php [R,L]
     DirectoryIndex index.php
   </Directory>
 
+</VirtualHost>