MFC r245571,245580:

MFC r245571,245580:

In preparation for logging metadata about each filesystem object,
refactor the link section of distrib-dirs to alwasy install to a full
path (the link contents remain relative as they should).

Eliminate the use of the "rm -r[f] <foo>; ln -s <bar> <foo>" pattern in
favor of "ln -sfh <bar> <foo>".  None of these links could be directories
on a system installed in the last decade.

Sponsored by:   DARPA, AFRL

git-svn-id: svn://svn.freebsd.org/base/stable/9@248351 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f