[MEDIUM] add a send limit to a buffer

For keep-alive, line-mode protocols and splicing, we will need to
limit the sender to process a certain amount of bytes. The limit
is automatically set to the buffer size when analysers are detached
from the buffer.
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index e31398a..21c50fc 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -799,6 +799,10 @@
 			resync = 1;
 	}
 
+	/* if noone is interested in analysing data, let's forward everything */
+	if (!s->req->analysers && !(s->req->flags & BF_HIJACK))
+		s->req->send_max = s->req->l;
+
 	/* reflect what the L7 analysers have seen last */
 	rqf_last = s->req->flags;
 
@@ -869,6 +873,10 @@
 			resync = 1;
 	}
 
+	/* if noone is interested in analysing data, let's forward everything */
+	if (!s->rep->analysers && !(s->rep->flags & BF_HIJACK))
+		s->rep->send_max = s->rep->l;
+
 	/* reflect what the L7 analysers have seen last */
 	rpf_last = s->rep->flags;