MINOR: systemd: remove comment about HAPROXY_STATS_SOCKET

This variable was used by the wrapper which was removed in
a6cfa9098e. The correct way to do seamless reload is now to enable
"expose-fd listeners" on the stat socket.

contrib/systemd/haproxy.service.in

@@ -3,8 +3,6 @@ Description=HAProxy Load Balancer
 After=network.target
 
 [Service]
-# You can point the environment variable HAPROXY_STATS_SOCKET to a stats
-# socket if you want seamless reloads.
 Environment="CONFIG=/etc/haproxy/haproxy.cfg" "PIDFILE=/run/haproxy.pid"
 ExecStartPre=@SBINDIR@/haproxy -f $CONFIG -c -q
 ExecStart=@SBINDIR@/haproxy -Ws -f $CONFIG -p $PIDFILE