mirrors: Restart on failure only (#982)

* Remove start limits and restart parameters

This has been very flaky and breaks a LOT of mirrors healthchecks. I'll have to look into how they interact later.

* Mirrors restart on failure

Author: ja5087

modules/ocf_mirrors/templates/systemd/monitor.service.erb

@@ -11,5 +11,5 @@ Environment="<%= env %>=<%= val %>"
 <% end -%>
 ExecStart=<%= @exec_start %>
 RuntimeMaxSec=10
-Restart=always
+Restart=on-failure
 RestartSec=5