upstream: Remove crc32.{c,h} which were only used by the now-gone

SSH1 protocol. Patch from yumkam at gmail.com, ok deraadt.

OpenBSD-Commit-ID: cceda5876c5ba6b4d8abcd52335329198cee3240
diff --git a/packet.c b/packet.c
index 36e352b..01d65c5 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.283 2019/03/01 03:29:32 djm Exp $ */
+/* $OpenBSD: packet.c,v 1.284 2019/04/18 07:32:57 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -77,7 +77,6 @@
 #include <zlib.h>
 
 #include "xmalloc.h"
-#include "crc32.h"
 #include "compat.h"
 #include "ssh2.h"
 #include "cipher.h"