Cleanup: Remove src/trusted/gio/, since it is unused

SConstruct

 #! -*- python -*-
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import atexit
 import json
 import os
 import platform
 import re
@@ skipping 2211 matching lines @@
       'src/shared/srpc/build.scons',
       'src/shared/utils/build.scons',
       'src/third_party/gtest/build.scons',
       'src/tools/validator_tools/build.scons',
       'src/trusted/cpu_features/build.scons',
       'src/trusted/debug_stub/build.scons',
       'src/trusted/desc/build.scons',
       'src/trusted/desc_cacheability/build.scons',
       'src/trusted/fault_injection/build.scons',
       'src/trusted/generic_container/build.scons',
-      'src/trusted/gio/build.scons',
       'src/trusted/interval_multiset/build.scons',
       'src/trusted/manifest_name_service_proxy/build.scons',
       'src/trusted/nacl_base/build.scons',
       'src/trusted/nonnacl_util/build.scons',
       'src/trusted/perf_counter/build.scons',
       'src/trusted/platform_qualify/build.scons',
       'src/trusted/reverse_service/build.scons',
       'src/trusted/seccomp_bpf/build.scons',
       'src/trusted/sel_universal/build.scons',
       'src/trusted/service_runtime/build.scons',
@@ skipping 1770 matching lines @@
   nacl_env.ValidateSdk()
 
 if BROKEN_TEST_COUNT > 0:
   msg = "There are %d broken tests." % BROKEN_TEST_COUNT
   if GetOption('brief_comstr'):
     msg += " Add --verbose to the command line for more information."
   print msg
 
 # separate warnings from actual build output
 Banner('B U I L D - O U T P U T:')