upstream: revert r1.399 - the lifetime of c->mux_ctx is more complex;

simply freeing it here causes other problems

OpenBSD-Commit-ID: c6fee8ca94e2485faa783839541962be2834c5ed

channels.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.399 2020/07/03 05:08:41 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.400 2020/07/03 07:17:35 djm Exp $ */
 /*
  * Author: Tatu Ylonen <[email protected]>
  * Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland
@@ -621,8 +621,6 @@ channel_free(struct ssh *ssh, Channel *c)
 	c->path = NULL;
 	free(c->listening_addr);
 	c->listening_addr = NULL;
-	free(c->mux_ctx);
-	c->mux_ctx = NULL;
 	while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 		if (cc->abandon_cb != NULL)
 			cc->abandon_cb(ssh, c, cc->ctx);