MINOR: proto_htx: Add functions htx_req_replace_stline and htx_res_set_status

It is more or less the same than legacy versions but adapted to be called from
HTX analyzers. In the legacy versions of these functions, we switch on the HTX
code when applicable.
diff --git a/include/proto/proto_http.h b/include/proto/proto_http.h
index 0d126d6..0598df8 100644
--- a/include/proto/proto_http.h
+++ b/include/proto/proto_http.h
@@ -70,6 +70,9 @@
 int htx_apply_redirect_rule(struct redirect_rule *rule, struct stream *s, struct http_txn *txn);
 int htx_transform_header_str(struct stream* s, struct channel *chn, struct htx *htx,
 			     struct ist name, const char *str, struct my_regex *re, int action);
+int htx_req_replace_stline(int action, const char *replace, int len,
+			   struct proxy *px, struct stream *s);
+void htx_res_set_status(unsigned int status, const char *reason, struct stream *s);
 void htx_server_error(struct stream *s, struct stream_interface *si, int err, int finst, const struct buffer *msg);
 void htx_reply_and_close(struct stream *s, short status, struct buffer *msg);