Harmonize flags.

The udp service was not passing the same arguments as the tcp one, this fixes
the missing --syslog flag

conf/services.d/openvpn-udp/run

 #!/bin/sh
 
 echo "Starting openvpn: udp"
-exec /usr/sbin/openvpn --cd /etc/openvpn --config /etc/openvpn/udp.conf
+exec /usr/sbin/openvpn --syslog ovpn-udp-server --cd /etc/openvpn --config /etc/openvpn/udp.conf