crypto/ssh: fix the links to the SSH protocol documents

Minor change - updated the links to the ssh PROTOCOL.* docs.
Currently the [PROTOCOL...] links in References on top of
https://godoc.org/golang.org/x/crypto/ssh and
https://godoc.org/golang.org/x/crypto/ssh/agent
take you to the top-level directory list on
http://cvsweb.openbsd.org/cgi-bin/cvsweb/
instead of directly to the respective document pages.

Change-Id: Ifd3f0bc2ef393ab02f023c13b93340fdb0a05af3
Reviewed-on: https://go-review.googlesource.com/8963
Reviewed-by: Adam Langley <agl@golang.org>
diff --git a/ssh/agent/client.go b/ssh/agent/client.go
index 1a91696..31a0120 100644
--- a/ssh/agent/client.go
+++ b/ssh/agent/client.go
@@ -6,7 +6,7 @@
   Package agent implements a client to an ssh-agent daemon.
 
 References:
-  [PROTOCOL.agent]:    http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.agent
+  [PROTOCOL.agent]:    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.agent?rev=HEAD
 */
 package agent // import "golang.org/x/crypto/ssh/agent"
 
diff --git a/ssh/doc.go b/ssh/doc.go
index fb6402b..d6be894 100644
--- a/ssh/doc.go
+++ b/ssh/doc.go
@@ -12,7 +12,7 @@
 others.
 
 References:
-  [PROTOCOL.certkeys]: http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys
+  [PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
   [SSH-PARAMETERS]:    http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
 */
 package ssh // import "golang.org/x/crypto/ssh"