[MINOR] stats: report the number of requests intercepted by the frontend

These requests are mainly monitor requests, as well as stats requests when
the stats are processed by the frontend. Having this counter helps explain
the difference in number of sessions that is sometimes observed between a
frontend and a backend.
diff --git a/src/dumpstats.c b/src/dumpstats.c
index 814a90c..d976e07 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -2286,7 +2286,8 @@
 					for (i = 1; i < 6; i++)
 						chunk_printf(&msg, " %dxx=%lld,", i, px->fe_counters.p.http.rsp[i]);
 
-					chunk_printf(&msg, " other=%lld\"", px->fe_counters.p.http.rsp[0]);
+					chunk_printf(&msg, " other=%lld,", px->fe_counters.p.http.rsp[0]);
+					chunk_printf(&msg, " intercepted=%lld\"", px->fe_counters.intercepted_req);
 				}
 
 				chunk_printf(&msg,
diff --git a/src/proto_http.c b/src/proto_http.c
index 26b8f73..bf21ca9 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -2670,6 +2670,7 @@
 		struct acl_cond *cond;
 
 		s->flags |= SN_MONITOR;
+		s->fe->fe_counters.intercepted_req++;
 
 		/* Check if we want to fail this monitor request or not */
 		list_for_each_entry(cond, &s->fe->mon_fail_cond, list) {
@@ -3275,6 +3276,8 @@
 		s->rep->prod->applet.private = s;
 		s->rep->prod->applet.st0 = s->rep->prod->applet.st1 = 0;
 		req->analysers = 0;
+		if (s->fe == s->be) /* report it if the request was intercepted by the frontend */
+			s->fe->fe_counters.intercepted_req++;
 
 		return 0;