MFC r279083:

MFC r279083:

  Fix the logic for skipping parameters (with -s) that have "jailsys"
  parents (such as host.hostname); these were being skipped all the time.
  That it went this long without anyone noticing is a sign that this feature
  isn't actually used by anyone, but it's there so it might as well work.

MFC r279123:

  Allow for parameters added with the JP_OPT flag to not exist.
  That's why the flag exists in the first place.

git-svn-id: svn://svn.freebsd.org/base/stable/10@279348 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f