MINOR: log: adds counters on received syslog messages.

This patch adds a global counter of received syslog messages
and this one is exported on CLI "show info" as "CumRecvLogs".

This patch also updates internal conn counter and freq
of the listener and the proxy for each received log message to
prepare a further export on the "show stats".
diff --git a/src/log.c b/src/log.c
index f8ac522..495a672 100644
--- a/src/log.c
+++ b/src/log.c
@@ -45,6 +45,8 @@
 #include <haproxy/tools.h>
 #include <haproxy/version.h>
 
+/* global recv logs counter */
+int cum_log_messages;
 
 /* log forward proxy list */
 struct proxy *cfg_log_forward;
@@ -3538,6 +3540,10 @@
 			}
 			buf->data = ret;
 
+			/* update counters */
+			_HA_ATOMIC_ADD(&cum_log_messages, 1);
+			proxy_inc_fe_conn_ctr(l, l->bind_conf->frontend);
+
 			parse_log_message(buf->area, buf->data, &level, &facility, metadata, &message, &size);
 
 			process_send_log(&l->bind_conf->frontend->logsrvs, level, facility, metadata, message, size);