While this still doesn't affect the behavior of the daemon, the
configuration option can at least be set to check the correct privsep
directory for permissions. Revisit in 5.8 as a possible extension to the
runtime check instead to remove the 'knob'.
This has effectively been a no-op during the 5.7 release series and
nobody has yelped (other than being slightly confused about its
purpose). Remove it as an option, since the home dir of the privsep user
is always used as the actual privsep directory anyway.