BUG/MINOR: proxy: inc req counter on new syslog messages.

Increase req counter instead of conn counter on
new syslog messages.

This should be backported on branches including the
syslog forward feature.
diff --git a/src/log.c b/src/log.c
index 2a49561..22f3caa 100644
--- a/src/log.c
+++ b/src/log.c
@@ -3545,7 +3545,7 @@
 
 			/* update counters */
 			_HA_ATOMIC_ADD(&cum_log_messages, 1);
-			proxy_inc_fe_conn_ctr(l, l->bind_conf->frontend);
+			proxy_inc_fe_req_ctr(l, l->bind_conf->frontend);
 
 			parse_log_message(buf->area, buf->data, &level, &facility, metadata, &message, &size);