Use block/rescue for image pre-stage

Move to usage of block/rescue for image pre-stage step.

Change-Id: I4ec91f541e6d2d4cca4d899f4c7d519b169e2f50
Co-Authored-By: Jesse Pretorius <jesse@odyssey4.me>

tasks/lxc_cache_preparation_systemd_new.yml

@@ -23,26 +23,25 @@
   when:
     - lxc_image_cache_refresh | bool
 
-- name: Ensure image has been pre-staged
-  async_status:
-    jid: "{{ prestage_image.ansible_job_id }}"
-  register: job_result
-  until: job_result.finished
-  ignore_errors: true
-  retries: 60
-
-- name: Trying to download image with alternate method
-  get_url:
-    url: "{{ lxc_hosts_container_image_url }}"
-    dest: "/tmp/{{ cache_basename }}"
-    validate_certs: "{{ (lxc_hosts_validate_certs | bool) | lower }}"
-    force: true
-    timeout: 15
-  register: image_download
-  until: image_download is success
-  retries: 3
-  delay: 2
-  when: job_result.failed
+- block:
+    - name: Ensure image has been pre-staged
+      async_status:
+        jid: "{{ prestage_image.ansible_job_id }}"
+      register: job_result
+      until: job_result.finished
+      retries: 60
+  rescue:
+    - name: Trying to download image with alternate method
+      get_url:
+        url: "{{ lxc_hosts_container_image_url }}"
+        dest: "/tmp/{{ cache_basename }}"
+        validate_certs: "{{ (lxc_hosts_validate_certs | bool) | lower }}"
+        force: true
+        timeout: 15
+      register: image_download
+      until: image_download is success
+      retries: 3
+      delay: 2
 
 - name: Ensure systemd-importd is enabled
   systemd:

tasks/lxc_cache_preparation_systemd_old.yml

@@ -32,26 +32,25 @@
   when:
     - lxc_image_cache_refresh | bool
 
-- name: Ensure image has been pre-staged
-  async_status:
-    jid: "{{ prestage_image.ansible_job_id }}"
-  register: job_result
-  until: job_result.finished
-  ignore_errors: true
-  retries: 60
-
-- name: Trying to download image with alternate method
-  get_url:
-    url: "{{ lxc_hosts_container_image_url }}"
-    dest: "/tmp/{{ cache_basename }}"
-    validate_certs: "{{ (lxc_hosts_validate_certs | bool) | lower }}"
-    force: true
-    timeout: 15
-  register: image_download
-  until: image_download is success
-  retries: 3
-  delay: 2
-  when: job_result.failed
+- block:
+    - name: Ensure image has been pre-staged
+      async_status:
+        jid: "{{ prestage_image.ansible_job_id }}"
+      register: job_result
+      until: job_result.finished
+      retries: 60
+  rescue:
+    - name: Trying to download image with alternate method
+      get_url:
+        url: "{{ lxc_hosts_container_image_url }}"
+        dest: "/tmp/{{ cache_basename }}"
+        validate_certs: "{{ (lxc_hosts_validate_certs | bool) | lower }}"
+        force: true
+        timeout: 15
+      register: image_download
+      until: image_download is success
+      retries: 3
+      delay: 2
 
 - name: Place container rootfs
   unarchive: