Deprecate nova::cert

Nova Cert has been removed from Nova:
d6d5c6be0c

Let's deprecate it in puppet-nova.

Change-Id: If1bb581c6fa2aeba1d29464221e541e35aa46d74

manifests/cert.pp

@@ -25,6 +25,8 @@ class nova::cert(
   include ::nova::deps
   include ::nova::params
 
+  warning('nova::cert class is deprecated and will be removed in Queens.')
+
   nova::generic_service { 'cert':
     enabled        => $enabled,
     manage_service => $manage_service,

releasenotes/notes/nova-cert-72762e4f0850ad58.yaml

@@ -0,0 +1,4 @@
+---
+deprecations:
+  - nova::cert is deprecated and will be removed in Queens.
+    Nova removed the cert daemon during Pike cycle.

spec/acceptance/nova_wsgi_apache_spec.rb

@@ -69,7 +69,6 @@ describe 'basic nova' do
       class { '::nova::placement':
         password => 'a_big_secret',
       }
-      class { '::nova::cert': }
       class { '::nova::client': }
       class { '::nova::conductor': }
       class { '::nova::consoleauth': }