Fix rc.d/gssd script to define the default values in a standard way.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270780 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
- Add a warning message when an IPv6 address is specified with no prefixlen.
- Use a parameter argument in jls(8) instead of doing grep.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270781 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f