[playbook] make sure playbook works with old version of ansible

playbook/roles/upgrade-apt/tasks/main.yml

@@ -5,7 +5,6 @@
 - name: get packages to upgrade
   shell: grep-status -X -S apt -ns Package
   register: packages_to_upgrade
-  check_mode: no
 
 - name: Upgrade all apt related packages
   apt: name={{ packages_to_upgrade.stdout.split('\n') }} state=latest

playbook/roles/vifib-server/handlers/main.yml

----
-
-  - name: Update cron service definition
-    # For ansible version < 2.4, state=restarted is mandatory to
-    # apply the changes (daemon_reload=yes only is not enough)
-    systemd: daemon_reload=yes name=cron state=restarted

playbook/roles/vifib-server/tasks/main.yml

@@ -32,7 +32,6 @@
   - name: Get systemd version
     shell: systemd --version | head -n 1 | cut -d " " -f 2
     register: systemd_version
-    check_mode: no
 
   - file: state=directory path="/etc/systemd/system/cron.service.d/"
     when: systemd_version.stdout | int > 228
@@ -40,5 +39,3 @@
   - name: Increase the maximum of subprocesses for cron
     copy: src="etc_systemd_system_cron_service_d_override.conf" dest="/etc/systemd/system/cron.service.d/override.conf" mode=0644 owner=root group=root
     when: systemd_version.stdout | int > 228
-    notify:
-      - "Update cron service definition"