BUG/MEDIUM: h2: properly send the GOAWAY frame in the mux

A typo on a condition prevented H2_CS_ERROR from being processed,
leading to an infinite loop on connection error.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 28b1684..aea1f98 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -1871,7 +1871,7 @@
 	}
 
  fail:
-	if (unlikely(h2c->st0 > H2_CS_ERROR)) {
+	if (unlikely(h2c->st0 >= H2_CS_ERROR)) {
 		if (h2c->st0 == H2_CS_ERROR) {
 			if (h2c->max_id >= 0) {
 				h2c_send_goaway_error(h2c, NULL);