Add experimental puppet 4 apply-test jobs

Fix the centos-7 job to actually use puppet 4 and add an experimental
puppet 4 job for ubuntu-xenial.

Change-Id: I33041a30f036673ef5e82b83e5eae933b4168f5b
Story: #2000243

playbooks/infra-puppet-apply/run.yaml

@@ -1,8 +1,12 @@
 - hosts: all
-  name: infra-puppet-apply-3
+  name: infra-puppet-apply
   tasks:
 
     - name: Run puppet-apply test
-      command: ./tools/apply-test.sh
+      shell: ./tools/apply-test.sh
       args:
         chdir: "{{ zuul.projects['git.openstack.org/openstack-infra/system-config'].src_dir }}"
+      environment:
+        PUPPET_VERSION: "{{ puppet_version | default('3') }}"
+      tags:
+        - skip_ansible_lint

zuul.d/jobs.yaml

@@ -1203,6 +1203,14 @@
     name: infra-puppet-apply-4-centos-7
     parent: infra-puppet-apply-base
     nodeset: centos-7
+    vars:
+      puppet_version: 4
+
+- job:
+    name: infra-puppet-apply-4-ubuntu-xenial
+    parent: infra-puppet-apply-base
+    vars:
+      puppet_version: 4
 
 - job:
     name: ansible-role-functional-base

zuul.d/zuul-legacy-project-templates.yaml

@@ -63,6 +63,7 @@
     experimental:
       jobs:
         - infra-puppet-apply-4-centos-7
+        - infra-puppet-apply-4-ubuntu-xenial
 
 - project-template:
     name: infra-puppet-check-jobs