Use ansible_service_mgr fact

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

Partial-Bug: #1640125
Change-Id: I51477047118e2b9460b7f4af5aa6f819befc7f28

tasks/glance_init_common.yml

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

tasks/main.yml

@@ -25,19 +25,6 @@
   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: glance_pre_install.yml
   tags:
     - glance-install