BUG/MEDIUM: mux-h1: Release the mux H1 in h1_process() if there is no h1s

With the current design, there is always an H1 stream attached to the mux. So
after the conn_stream is detached, if we don't create a new H1 stream in
h1_process(), it is important to release the mux.

src/mux_h1.c

@@ -1600,6 +1600,8 @@ static int h1_process(struct h1c * h1c)
 			if (!h1s_create(h1c, NULL))
 				goto release;
 		}
+		else
+			goto release;
 		h1s = h1c->h1s;
 	}