TEST-06-SELINUX: Relabel in the initrd rather than at image build time

This gets rid of the requirement to run the image build as root.

test/integration-tests/TEST-06-SELINUX/meson.build

@@ -1,19 +1,20 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
-id = find_program('id', required : true)
-uid = run_command(id, '-u', check : true).stdout().strip().to_int()
-
 integration_tests += [
         integration_test_template + {
                 'name' : fs.name(meson.current_source_dir()),
-                'cmdline' : integration_test_template['cmdline'] + ['selinux=1', 'enforcing=0', 'lsm=selinux'],
+                'cmdline' : integration_test_template['cmdline'] + [
+                        'selinux=1',
+                        'enforcing=0',
+                        'lsm=selinux',
+                        'rd.systemd.wants=initrd-selinux-relabel.service',
+                ],
                 # FIXME; Figure out why reboot sometimes hangs with 'linux' firmware.
                 # Use 'auto' to automatically fallback on non-uefi architectures.
                 'firmware' : 'auto',
                 'vm' : true,
-                # Make sure we don't mount anything with virtiofs as otherwise fixfiles will try to relabel
+                # Make sure we don't mount anything with virtiofs as otherwise setfiles will try to relabel
                 # it.
                 'mkosi-args' : integration_test_template['mkosi-args'] + ['--runtime-build-sources=no'],
-                'enabled' : uid == 0,
         },
 ]