BUG/MINOR: stream: Don't incr frontend cum_req counter when stream is closed

This counter is already incremented when a new request is received (or if an
error occurred waiting it). So it must not be incremented when the stream is
terminated, at the end of process_strem(). This bug was introduced by the commit
cff0f739e ("MINOR: counters: Review conditions to increment counters from
analysers").

No backport needed.
diff --git a/src/stream.c b/src/stream.c
index 38f1e4f..b36d709 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -2394,7 +2394,6 @@
 
 		if (sess->fe->mode == PR_MODE_HTTP) {
 			_HA_ATOMIC_ADD(&sess->fe->fe_counters.p.http.rsp[n], 1);
-			_HA_ATOMIC_ADD(&sess->fe->fe_counters.p.http.cum_req, 1);
 		}
 		if ((s->flags & SF_BE_ASSIGNED) &&
 		    (s->be->mode == PR_MODE_HTTP)) {