BUG/MINOR: rules: Preserve FLT_END analyzers on silent-drop action

When at least a filter is attached to a stream, FLT_END analyzers must be
preserved on request and response channels.

This patch should be backported as far as 1.7.

(cherry picked from commit 177f480f2c5b6a73b148a7069a71ddbff3e9f6a6)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit e15005b1f975a82126f29d912cd9e5419448c845)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 502e736..0ae53c4 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -1350,9 +1350,8 @@
 	if (strm) {
 		channel_abort(&strm->req);
 		channel_abort(&strm->res);
-		strm->req.analysers = 0;
-		strm->res.analysers = 0;
-		_HA_ATOMIC_ADD(&strm->be->be_counters.denied_req, 1);
+		strm->req.analysers &= AN_REQ_FLT_END;
+		strm->res.analysers &= AN_RES_FLT_END;
 		if (!(strm->flags & SF_ERR_MASK))
 			strm->flags |= SF_ERR_PRXCOND;
 		if (!(strm->flags & SF_FINST_MASK))