openvpn-exporter: stop trying to scrape the udp status path

We aren't currently running a udp server

chaperone.d/openvpn_exporter.conf

 openvpn-exporter.service: {
-     command: "/usr/local/bin/openvpn_exporter -openvpn.status_paths /tmp/openvpn-status-tcp,/tmp/openvpn-status-udp",
+     command: "/usr/local/bin/openvpn_exporter -openvpn.status_paths /tmp/openvpn-status-tcp",
      exit_kills: false
 }