The sreview role should not try to restart sreview-dispatch unless the host also has the sreview-master role

roles/sreview/handlers/main.yml has a handler to restart the sreview-dispatch service if the SReview configuration file is updated.

However, the sreview-dispatch service is only installed on hosts that also have the sreview-master role. On hosts that don't (usually encoders), trying to restart sreview-dispatch will fail because the sreview-dispatch.service systemd unit does not exist.

This should be remedied, either by skipping the restart if the sreview-master role is not enabled, or by ignoring the error.