[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,