Fix bootstrap-host authorized_key transfer for multi-nodes

This ensures the lookup has something to lookup and doesn't assume
that the operation will run as in the root folder by default. This
assumption was fine for an AIO, but the process has to be done
differently for multi nodes.

Change-Id: Ia4121ebe8b4d64fd81ce779330d659bb954e4079
Signed-off-by: Jean-Philippe Evrard <jean-philippe@evrard.me>

tests/roles/bootstrap-host/tasks/prepare_ssh_keys.yml

@@ -57,11 +57,19 @@
   tags:
     - ssh-key-generate
 
-- name: Ensure root's new public ssh key is in authorized_keys
-  authorized_key:
-    user: root
-    key: "{{ lookup('file', '/root/.ssh/id_rsa.pub') }}"
-    manage_dir: no
+- name: Fetch the generated public ssh key
+  fetch:
+    src: "/root/.ssh/id_rsa.pub"
+    dest: "/tmp/id_rsa.pub"
+    flat: yes
+  when: inventory_hostname == groups['all'][0]
   tags:
     - ssh-key-authorized
 
+- name: Ensure root's new public ssh key is in authorized_keys
+  authorized_key:
+    user: root
+    key: "{{ lookup('file','/tmp/id_rsa.pub') }}"
+    manage_dir: no
+  tags:
+    - ssh-key-authorized