Use chain-loading for Linux nacl_helper

chrome/tools/build/linux/FILES.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # Copyright (c) 2010 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.
 
 # This is a buildbot configuration file containing a tagged list of files
 # processed by the stage/archive scripts. The known tags are:
 #
@@ skipping 106 matching lines @@
     'filename': 'nacl_irt_x86_32.nexe',
     'arch': ['32bit'],
     'buildtype': ['dev', 'official'],
   },
   {
     'filename': 'nacl_irt_x86_64.nexe',
     'arch': ['64bit'],
     'buildtype': ['dev', 'official'],
   },
   {
-    'filename': 'nacl_helper.so',
+    'filename': 'nacl_helper',
     'arch': ['32bit', '64bit'],
     'buildtype': ['dev', 'official'],
   },
   {
     'filename': 'nacl_helper_bootstrap',
     'arch': ['32bit', '64bit'],
     'buildtype': ['dev', 'official'],
   },
   # Remoting files:
   {
     'filename': 'remoting-it2me.zip',
     'arch': ['32bit', '64bit'],
     'buildtype': ['dev', 'official'],
     'archive': 'remoting-it2me.zip',
   },
 ]