Use ansible_service_mgr fact

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

Partial-Bug: #1640125
Change-Id: Ie23bdd2fe44d22ff19699f5c9bef9a71d190be45

tasks/main.yml

@@ -13,20 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Detect whether the init system is upstart of systemd.
-- 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
-
 - name: Gather variables for each operating system
   include_vars: "{{ item }}"
   with_first_found:

tasks/nova_disable_smt.yml

@@ -28,7 +28,7 @@
     owner: "root"
     group: "root"
   when:
-    - pid1_name == "systemd"
+    - ansible_service_mgr == 'systemd'
   notify:
     - Reload systemd daemon
 
@@ -37,6 +37,6 @@
     src: "smt.conf"
     dest: "/etc/init/smt.conf"
   when:
-    - pid1_name != "systemd"
+    - ansible_service_mgr != 'systemd'
   notify:
     - Reload upstart init scripts

tasks/nova_init_common.yml

@@ -14,10 +14,12 @@
 # limitations under the License.
 
 - include: nova_init_upstart.yml
-  when: pid1_name == "init"
+  when:
+    - ansible_service_mgr == 'upstart'
 
 - include: nova_init_systemd.yml
-  when: pid1_name == "systemd"
+  when:
+    - ansible_service_mgr == 'systemd'
 
 - name: Load service
   service: