"even after server reboot" may be the key clue to your problem. You've got some init routine that is starting /cms/plone4. There's a good chance that it's a monitoring routine that watches the Plone process and restarts it if it stops. An example of that kind of process monitor (and one that's very popular among Plone integrators) is supervisor.
So, track down the routine that's starting /cms/plone4 on system restart. Change its setup to exclude /cms/plone4 and replace it with the new one.