Add libpeerconnection.so to FILES.cfg for linux and chromeos.

chrome/tools/build/linux/FILES.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # 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.
 
 # This is a buildbot configuration file containing a tagged list of files
 # processed by the stage/archive scripts. The known tags are:
 #
@@ skipping 46 matching lines @@
   },
   {
     'filename': 'installer',
     'buildtype': ['official'],
   },
   {
     'filename': 'libffmpegsumo.so',
     'buildtype': ['dev', 'official'],
   },
   {
+    'filename': 'lib/libpeerconnection.so',
+    'buildtype': ['dev', 'official'],
+    'optional': ['dev', 'official'],
+  },
+  {
     'filename': 'locales',
     'buildtype': ['dev', 'official'],
   },
   {
     'filename': 'product_logo_48.png',
     'buildtype': ['dev', 'official'],
   },
   {
     'filename': 'resources',
     'buildtype': ['dev', 'official'],
@@ skipping 115 matching lines @@
     'buildtype': ['official'],
     'archive': 'breakpad-info.zip',
   },
   {
     'filename': 'libremoting_host_plugin.x64.so.breakpad.x64',
     'arch': ['64bit'],
     'buildtype': ['official'],
     'archive': 'breakpad-info.zip',
   },
 ]