deploy check_openvpn_server.pl after nagios-plugins-standard package is installed

Change-Id: I272b30fd79e89ddf968c0a6e453d53a1f0540397

puppet/modules/site_nagios/manifests/server.pp

+# configures nagios on monitoring node
 class site_nagios::server inherits nagios::base {
 
   # First, purge old nagios config (see #1467)
@@ -46,6 +47,7 @@ class site_nagios::server inherits nagios::base {
     mode    => '0755',
     owner   => 'nagios',
     group   => 'nagios',
+    require => Package['nagios-plugins'];
   }
 
   create_resources ( site_nagios::add_host_services, $nagios_hosts )