When choosing the option to harden reading the kernel message buffer by
an unprivileged user in bsdinstall, access to the kernel message buffer
is restricted via its sysctl (security.bsd.unprivileged_read_msgbuf=0).

In order for this setting to be effective, access to this data via
system logs must also be restricted. Add the necessary hooks to
restrict access to the log files:

• /var/log/messages
• /var/run/dmesg.boot ($dmesg_file)

PR: 272552