Linux: remove unmaintained SELinux code.

build/linux/system.gyp

 # 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.
 
 {
   'variables': {
     'conditions': [
       ['sysroot!=""', {
         'pkg-config': './pkg-config-wrapper "<(sysroot)" "<(target_arch)"',
       }, {
@@ skipping 605 matching lines @@
           },
           'link_settings': {
             'libraries': [
               '<!@(libgcrypt-config --libs)',
             ],
           },
         }],
       ],
     },
     {
-      'target_name': 'selinux',
-      'type': 'none',
-      'conditions': [
-        ['_toolset=="target"', {
-          'link_settings': {
-            'libraries': [
-              '-lselinux',
-            ],
-          },
-        }],
-      ],
-    },
-    {
       'target_name': 'gnome_keyring',
       'type': 'none',
       'conditions': [
         ['use_gnome_keyring==1', {
           'direct_dependent_settings': {
             'cflags': [
               '<!@(<(pkg-config) --cflags gnome-keyring-1)',
             ],
             'defines': [
               'USE_GNOME_KEYRING',
@@ skipping 185 matching lines @@
             ],
             'libraries': [
               '<!@(<(pkg-config) --libs-only-l libudev)',
             ],
           },
         }],
       ],
     },
   ],
 }