[NaCl SDK]: nacl_io: add nacl_io_uninit function.

native_client_sdk/src/libraries/nacl_io/nacl_io.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "nacl_io/nacl_io.h"
 
 #include <stdlib.h>
 #include "nacl_io/kernel_intercept.h"
 #include "nacl_io/kernel_proxy.h"
 
 void nacl_io_init() {
   ki_init(NULL);
 }
 
+void nacl_io_uninit() {
+  ki_uninit();
+}
+
 void nacl_io_init_ppapi(PP_Instance instance, PPB_GetInterface get_interface) {
   ki_init_ppapi(NULL, instance, get_interface);
 }
 
 int nacl_io_register_fs_type(const char* fs_type, fuse_operations* fuse_ops) {
   return ki_get_proxy()->RegisterFsType(fs_type, fuse_ops);
 }
 
 int nacl_io_unregister_fs_type(const char* fs_type) {
   return ki_get_proxy()->UnregisterFsType(fs_type);
 }
 
 void nacl_io_set_exit_callback(nacl_io_exit_callback_t exit_callback,
                                void* user_data) {
   ki_get_proxy()->SetExitCallback(exit_callback, user_data);
 }
 
 void nacl_io_set_mount_callback(nacl_io_mount_callback_t callback,
                                 void* user_data) {
   ki_get_proxy()->SetMountCallback(callback, user_data);
 }