Update etcd client to 3.3.9

vendor/github.com/gorilla/websocket/conn_read.go

@@ -0,0 +1,18 @@
+// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.5
+
+package websocket
+
+import "io"
+
+func (c *Conn) read(n int) ([]byte, error) {
+	p, err := c.br.Peek(n)
+	if err == io.EOF {
+		err = errUnexpectedEOF
+	}
+	c.br.Discard(len(p))
+	return p, err
+}