Added virtio nic support

manifests/compute.pp

@@ -8,7 +8,8 @@ class nova::compute(
   $vncproxy_host                 = false,
   $vncproxy_protocol             = 'http',
   $vncproxy_port                 = '6080',
-  $vncproxy_path                 = '/vnc_auto.html'
+  $vncproxy_path                 = '/vnc_auto.html',
+  $virtio_nic                    = true
  ) {
 
   include nova::params
@@ -44,4 +45,9 @@ class nova::compute(
     before         => Exec['networking-refresh']
   }
 
+  if $virtio_nic {
+    # Enable the virtio network card for instances
+    nova_config { 'libvirt_use_virtio_for_bridges': value => 'True' }
+  }
+
 }