MINOR: mux-h1: Disable reads if an error was reported on the H1 stream

Don't try to read more data if a parsing or a formatting error was reported
on the H1 stream. There is no reason to continue to process the messages for
the current connection in this case. If a parsing error occurs, it means the
input is invalid. If a formatting error occurs, it is an internal error and
it is probably safer to give up.
diff --git a/src/mux_h1.c b/src/mux_h1.c
index 682776f..fa5c2da 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -356,11 +356,14 @@
 /*
  * Indicates whether or not we may receive data. The rules are the following :
  *   - if an error or a shutdown for reads was detected on the connection we
-       must not attempt to receive
+ *      must not attempt to receive
+ *   - if we are waiting for the connection establishment, we must not attempt
+ *      to receive
+ *   - if an error was detected on the stream we must not attempt to receive
+ *   - if reads are explicitly disabled, we must not attempt to receive
  *   - if the input buffer failed to be allocated or is full , we must not try
  *     to receive
- *   - if he input processing is busy waiting for the output side, we may
- *     attempt to receive
+ *   - if the mux is not blocked on an input condition, we may attempt to receive
  *   - otherwise must may not attempt to receive
  */
 static inline int h1_recv_allowed(const struct h1c *h1c)
@@ -375,6 +378,11 @@
 		return 0;
 	}
 
+	if (h1c->h1s && (h1c->h1s->flags & H1S_F_ERROR)) {
+		TRACE_DEVEL("recv not allowed because of error on h1s", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
+		return 0;
+	}
+
 	if (h1c->flags & H1C_F_WAIT_OPPOSITE) {
 		TRACE_DEVEL("recv not allowed (wait_opposite)", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
 		return 0;