Use ansible_service_mgr fact

This patch removes some extra tasks for detecting systemd and uses
the `ansible_service_mgr` fact instead.

Partial-Bug: #1640125
Change-Id: I4c35f5e92ea9ba4ed297c683aa4e8ebdcbe3fb4e

tasks/lxc_net.yml

@@ -51,7 +51,7 @@
     group: root
     mode: 0644
   when:
-    - pid1_name == "init"
+    - ansible_service_mgr == 'upstart'
   tags:
     - lxc-files
     - lxc-net
@@ -62,7 +62,7 @@
     path: /etc/systemd/system/lxc-net.service
     state: link
   when:
-    - pid1_name == "systemd"
+    - ansible_service_mgr == 'systemd'
   tags:
     - lxc-files
     - lxc-net

tasks/main.yml

@@ -42,19 +42,6 @@
   tags:
     - always
 
-- name: Check init system
-  command: cat /proc/1/comm
-  changed_when: false
-  register: _pid1_name
-  tags:
-    - always
-
-- name: Set the name of pid1
-  set_fact:
-    pid1_name: "{{ _pid1_name.stdout }}"
-  tags:
-    - always
-
 - include: lxc_pre_install.yml
 - include: lxc_install.yml
 - include: lxc_post_install.yml