Remove $FreeBSD$: one-line forth tag

Remove /^\\[\s*]*\$FreeBSD\$.*$\n/

Restore the ability to prevent the user from interrupting the boot process
without first entering the password stored in loader.conf(5).

PR: kern/207069
Reported by: david@dcrosstech.com
MFC after: 3 days
Sponsored by: Smule, Inc.

Move sys/boot to stand. Fix all references to new location

Sponsored by: Netflix