Fixed missing selinux context setup for live ISOs

When building live ISO images the selinux context was not created
for eventually new created files during the live ISO creation
process. This Fixes OSInside/kiwi-boxed-plugin#99

kiwi/bootloader/config/grub2.py

@@ -281,12 +281,15 @@ class BootLoaderConfigGrub2(BootLoaderConfigBase):
                 self.boot_directory_name, 'grub.cfg'
             ]
         )
+        # Disable os-prober, it takes information from the host it
+        # runs on which is not necessarily matching with the image
+        os.environ.update({'GRUB_DISABLE_OS_PROBER': 'true'})
         Command.run(
             [
                 'chroot', self.root_mount.mountpoint,
                 os.path.basename(self._get_grub2_mkconfig_tool()), '-o',
                 config_file.replace(self.root_mount.mountpoint, '')
-            ]
+            ], os.environ
         )
         if boot_options.get('root_device') != boot_options.get('boot_device'):
             # Create a boot -> . link on the boot partition.

kiwi/builder/live.py

@@ -189,6 +189,8 @@ class LiveImageBuilder:
             working_directory=self.root_dir
         )
 
+        self.system_setup.setup_selinux_file_contexts()
+
         # prepare dracut initrd call
         self.boot_image.prepare()
 
@@ -251,6 +253,9 @@ class LiveImageBuilder:
             'mount_options': self.xml_state.get_fs_mount_option_list(),
             'create_options': self.xml_state.get_fs_create_option_list()
         }
+
+        self.system_setup.setup_selinux_file_contexts()
+
         filesystem_setup = FileSystemSetup(
             self.xml_state, self.root_dir
         )

test/unit/bootloader/config/grub2_test.py

@@ -981,12 +981,13 @@ class TestBootLoaderConfigGrub2:
             mock_mount_system.assert_called_once_with(
                 'rootdev', 'bootdev', None, None, None
             )
+            os.environ.update({'GRUB_DISABLE_OS_PROBER': 'true'})
             assert mock_Command_run.call_args_list == [
                 call(
                     [
                         'chroot', self.bootloader.root_mount.mountpoint,
                         'grub2-mkconfig', '-o', '/boot/grub2/grub.cfg'
-                    ]
+                    ], os.environ
                 ),
                 call(
                     [

test/unit/builder/live_test.py

@@ -227,6 +227,10 @@ class TestLiveImageBuilder:
 
         self.setup.import_cdroot_files.assert_called_once_with('temp_media_dir')
 
+        assert self.setup.setup_selinux_file_contexts.call_args_list == [
+            call(), call()
+        ]
+
         assert kiwi.builder.live.FileSystem.new.call_args_list == [
             call(
                 device_provider=self.loop, name='ext4',