Fixes a hypothetical security issue related to privilege escalation via
rootwrap/privsep. A potential vulnerable service could previously allow
writes to its rootwrap/privsep config and thus allow for more commands
to be run with root privileges via rootwrap/privsep. For a succesful
attack, this would also require the service to allow to run arbitrary
commands via rootwrap/privsep. Thus far, no such vulnerabilities have
been reported and thus this fix is simply strengthening the container
images against such an issue in the future.
Change-Id: I92c81c77e6a16570a108cde8031f7977930fb02a
Closes-Bug: #1874298
2daf4331a6