Allow mistral role to pull images

Change-Id: Id5e56f62dff4fc7bc52641a56abab3ee88a25740
Partially-Implements: blueprint pre-pull-images

ansible/roles/mistral/tasks/deploy.yml

+---
+- include: register.yml
+  when: inventory_hostname in groups['mistral-api']
+
+- include: config.yml
+  when: inventory_hostname in groups['mistral-api'] or
+        inventory_hostname in groups['mistral-engine'] or
+        inventory_hostname in groups['mistral-executor']
+
+- include: bootstrap.yml
+  when: inventory_hostname in groups['mistral-api']
+
+- include: start.yml
+  when: inventory_hostname in groups['mistral-api'] or
+        inventory_hostname in groups['mistral-engine'] or
+        inventory_hostname in groups['mistral-executor']

ansible/roles/mistral/tasks/main.yml

 ---
-- include: register.yml
-  when: inventory_hostname in groups['mistral-api']
+- include: "{{ action }}.yml"
+  when: not common_run
 
-- include: config.yml
-  when: inventory_hostname in groups['mistral-api'] or
-        inventory_hostname in groups['mistral-engine'] or
-        inventory_hostname in groups['mistral-executor']
-
-- include: bootstrap.yml
-  when: inventory_hostname in groups['mistral-api']
-
-- include: start.yml
-  when: inventory_hostname in groups['mistral-api'] or
-        inventory_hostname in groups['mistral-engine'] or
-        inventory_hostname in groups['mistral-executor']
+- name: Registering common role has run
+  set_fact:
+    common_run: True
+  when: not common_run

ansible/roles/mistral/tasks/pull.yml

+---
+- name: Pulling mistral-api image
+  kolla_docker:
+    action: "pull_image"
+    common_options: "{{ docker_common_options }}"
+    image: "{{ mistral_api_image_full }}"
+  when: inventory_hostname in groups['mistral-api']
+
+- name: Pulling mistral-engine image
+  kolla_docker:
+    action: "pull_image"
+    common_options: "{{ docker_common_options }}"
+    image: "{{ mistral_engine_image_full }}"
+  when: inventory_hostname in groups['mistral-engine']
+
+- name: Pulling mistral-executor image
+  kolla_docker:
+    action: "pull_image"
+    common_options: "{{ docker_common_options }}"
+    image: "{{ mistral_executorngine_image_full }}"
+  when: inventory_hostname in groups['mistral-executor']