use dep as denpendency managment tool

vendor/golang.org/x/crypto/ssh/doc.go

@@ -1,18 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-Package ssh implements an SSH client and server.
-
-SSH is a transport security protocol, an authentication protocol and a
-family of application protocols. The most typical application level
-protocol is a remote shell and this is specifically implemented.  However,
-the multiplexed nature of SSH is exposed to users that wish to support
-others.
-
-References:
-  [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"