MFC r216591:

MFC r216591:
  Suggest to run the delete-old target after the second mergemaster. If you run
  it before, your rc scripts may still reference old files/directories and
  if you are in the unlucky situation to have triggered a reboot (intentionally
  or not) between the delete-old run and the mergemaster, your system may not
  start anymore.

  While I'm here, give a hint about delete-old-libs.

  Noticed by:        bcr (luckily in a discussion and not by getting hit by
                          this)

git-svn-id: svn://svn.freebsd.org/base/stable/8@219034 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f