Drop support for sysvinit scripts

As announced by a few releases now, finally drop support for
sysvinit scripts.
Keep rc-local generator for now, as it's really a distinct
feature even though from the same era.

tmpfiles.d/legacy.conf.in

@@ -16,9 +16,3 @@ L /var/lock - - - - ../run/lock
 {% if CREATE_LOG_DIRS %}
 L$ /var/log/README - - - - ../..{{DOC_DIR}}/README.logs
 {% endif %}
-
-{% if HAVE_SYSV_COMPAT %}
-# /run/lock/subsys is used for serializing SysV service execution, and
-# hence without use on SysV-less systems.
-d /run/lock/subsys 0755 root root -
-{% endif %}