Gate: Move pull images to its own playbook

This PS moves build images to its own playbook, reduducing the time
taken to run the gates when not required.

Change-Id: I17203a6fa2e3c7898175389f13d680fe9347b920

.zuul.yaml

@@ -101,6 +101,7 @@
     pre-run:
       - tools/gate/playbooks/osh-infra-deploy-docker.yaml
       - tools/gate/playbooks/osh-infra-build.yaml
+      - tools/gate/playbooks/osh-infra-pull-images.yaml
       - tools/gate/playbooks/osh-infra-deploy-k8s.yaml
     run: tools/gate/playbooks/osh-infra-deploy-charts.yaml
     post-run: tools/gate/playbooks/osh-infra-collect-logs.yaml

tools/gate/playbooks/osh-infra-build.yaml

@@ -34,14 +34,3 @@
     - build-images
   tags:
     - build-images
-
-- hosts: primary
-  vars_files:
-    - vars.yaml
-  vars:
-    work_dir: "{{ zuul.project.src_dir }}/{{ zuul_osh_infra_relative_path | default('') }}"
-  gather_facts: True
-  roles:
-    - pull-images
-  tags:
-    - pull-images

tools/gate/playbooks/osh-infra-pull-images.yaml

@@ -0,0 +1,24 @@
+# Copyright 2017 The Openstack-Helm Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+- hosts: all
+  vars_files:
+    - vars.yaml
+  vars:
+    work_dir: "{{ zuul.project.src_dir }}/{{ zuul_osh_infra_relative_path | default('') }}"
+  gather_facts: True
+  roles:
+    - pull-images
+  tags:
+    - pull-images