vrrp: log-facility should be a required_argument #61

Before:
`/usr/sbin/keepalived -n -f /etc/keepalived/keepalived.conf --log-facility`
Segmentation fault

After:
`/usr/sbin/keepalived -n -f /etc/keepalived/keepalived.conf --log-facility`
/usr/sbin/keepalived: option '--log-facility' requires an argument