Upgrading server dependancies (#6431)

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

@@ -2,20 +2,14 @@
 // this source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
+// +build !appengine
+
 package websocket
 
-import (
-	"math/rand"
-	"unsafe"
-)
+import "unsafe"
 
 const wordSize = int(unsafe.Sizeof(uintptr(0)))
 
-func newMaskKey() [4]byte {
-	n := rand.Uint32()
-	return [4]byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 24)}
-}
-
 func maskBytes(key [4]byte, pos int, b []byte) int {
 
 	// Mask one byte at a time for small buffers.