Fix Telegraf container restarting issue

Telegraf always restart containers when doing reconfigure, due to
"pid_mode" attribut missing during compare_container.
Hence compare_container always evaluated to True.

Change-Id: I335816ebf99a218a5400b2baae5b55788459bfff
Closes-Bug: #1686349

ansible/roles/telegraf/tasks/config.yml

@@ -56,6 +56,7 @@
     name: "{{ item.value.container_name }}"
     image: "{{ item.value.image }}"
     volumes: "{{ item.value.volumes }}"
+    pid_mode: "{{ item.value.pid_mode }}"
   register: check_telegraf_containers
   when:
     - action != "config"