Temporary fix of failing aria2 on centos

Added get_url as an alternate downloader, when aria2 is failing
due to SSL error. Now it happens for CentOS and is reproducable.
We probably won't need this patch once aria2 package will be fixed.

Change-Id: I7770c5417feacfc43a3ad8801125603a55ba9ea8

tasks/lxc_cache_preparation_systemd_new.yml

@@ -28,8 +28,17 @@
     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
+  when: job_result.failed
+
 - name: Ensure systemd-importd is enabled
   systemd:
     name: "systemd-importd"

tasks/lxc_cache_preparation_systemd_old.yml

@@ -37,8 +37,17 @@
     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
+  when: job_result.failed
+
 - name: Place container rootfs
   unarchive:
     src: "/tmp/{{ cache_basename }}"