Don't fail hard when facter cache doesn't work correctly

Since the facter cache is supposed to be a help but not necessarily a
hard requirement, let's make sure the tasks don't fail if something goes
wrong. We should output the error if the facter execution fails, but we
don't want to always output it.

Change-Id: I58d42c74295f031b260c0b67dbc12336fc31db1f
Related-Bug: #1852606

tripleo_ansible/roles/tripleo-puppet-cache/tasks/main.yml

@@ -83,6 +83,13 @@
   command: facter --config "{{ tripleo_puppet_cache_base_dir }}/facter.conf"
   no_log: true
   ignore_errors: true
+  register: _facter_cache_run
+
+- name: Facter error output when failed
+  check_mode: false
+  debug:
+    msg: "{{ _facter_cache_run.stderr }}"
+  when: _facter_cache_run is failed
 
 - name: Sync cached facts
   become: true
@@ -91,3 +98,4 @@
     src: "/opt/puppetlabs/"
     dest: "{{ tripleo_puppet_cache_base_dir }}/"
   delegate_to: "{{ inventory_hostname }}"
+  when: _facter_cache_run is succeeded