upstream: If select() fails in ssh_packet_read_seqnr go directly to

the error path instead of trying to read from the socket on the way out,
which resets errno and causes the true error to be misreported.  ok djm@

OpenBSD-Commit-ID: 2614edaadbd05a957aa977728aa7a030af7c6f0a
diff --git a/packet.c b/packet.c
index 574aef6..08a4d66 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.269 2017/12/18 23:13:42 djm Exp $ */
+/* $OpenBSD: packet.c,v 1.270 2018/05/25 03:20:59 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1338,8 +1338,10 @@
 			    NULL, NULL, timeoutp)) >= 0)
 				break;
 			if (errno != EAGAIN && errno != EINTR &&
-			    errno != EWOULDBLOCK)
-				break;
+			    errno != EWOULDBLOCK) {
+				r = SSH_ERR_SYSTEM_ERROR;
+				goto out;
+			}
 			if (state->packet_timeout_ms == -1)
 				continue;
 			ms_subtract_diff(&start, &ms_remain);