upgrade: Reload systemd before restart

The installer now lays down updated systemd unit files in
/etc/systemd/system/ which override the units that come with the
rpms. Because of this we need to reload systemd before restarting
services.

Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1455843

roles/openshift_node_upgrade/tasks/restart.yml

@@ -5,6 +5,14 @@
 # - openshift.common.hostname
 # - openshift.master.api_port
 
+# NOTE: This is needed to make sure we are using the correct set
+#       of systemd unit files. The RPMs lay down defaults but
+#       the install/upgrade may override them in /etc/systemd/system/.
+# NOTE: We don't use the systemd module as some versions of the module
+#       require a service to be part of the call.
+- name: Reload systemd to ensure latest unit files
+  command: systemctl daemon-reload
+
 - name: Restart docker
   service:
     name: "{{ openshift.docker.service_name }}"