upstream commit

Revise hostkeys@openssh.com hostkey learning extension.

The client will not ask the server to prove ownership of the private
halves of any hitherto-unseen hostkeys it offers to the client.

Allow UpdateHostKeys option to take an 'ask' argument to let the
user manually review keys offered.

ok markus@
diff --git a/ssherr.c b/ssherr.c
index 5c29c46..4ca7939 100644
--- a/ssherr.c
+++ b/ssherr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ssherr.c,v 1.3 2015/01/30 01:13:33 djm Exp $	*/
+/*	$OpenBSD: ssherr.c,v 1.4 2015/02/16 22:13:32 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -121,6 +121,8 @@
 		return "agent not present";
 	case SSH_ERR_AGENT_NO_IDENTITIES:
 		return "agent contains no identities";
+	case SSH_ERR_BUFFER_READ_ONLY:
+		return "internal error: buffer is read-only";
 	case SSH_ERR_KRL_BAD_MAGIC:
 		return "KRL file has invalid magic number";
 	case SSH_ERR_KEY_REVOKED: