enable libvirt at boot

When using libvirt driver, we need to ensure that libvirt service is
actually enabled at boot.

Change-Id: Ie3198010ca8cfbe515d4e99e2662330f6ac29290
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>

manifests/compute/libvirt.pp

@@ -69,6 +69,7 @@ class nova::compute::libvirt (
 
   service { 'libvirt' :
     ensure   => running,
+    enable   => true,
     name     => $::nova::params::libvirt_service_name,
     provider => $::nova::params::special_service_provider,
     require  => Package['libvirt'],

spec/classes/nova_compute_libvirt_spec.rb

@@ -26,6 +26,7 @@ describe 'nova::compute::libvirt' do
 
       it { should contain_service('libvirt').with(
         :name     => 'libvirt-bin',
+        :enable   => true,
         :ensure   => 'running',
         :provider => 'upstart',
         :require  => 'Package[libvirt]',
@@ -98,6 +99,7 @@ describe 'nova::compute::libvirt' do
 
       it { should contain_service('libvirt').with(
         :name     => 'libvirtd',
+        :enable   => true,
         :ensure   => 'running',
         :provider => 'init',
         :require  => 'Package[libvirt]',
@@ -172,6 +174,7 @@ describe 'nova::compute::libvirt' do
 
       it { should contain_service('libvirt').with(
         :name     => 'libvirtd',
+        :enable   => true,
         :ensure   => 'running',
         :provider => nil,
         :require  => 'Package[libvirt]',