Modify file permissions for shutdown(8), poweroff(8), mksnap_ffs(8) and ppp(8) so they are readable by others.

[neel]

Test Plan

Install world and verify permissions.

-r-sr-xr-- 1 root operator 9944 Aug 20 16:04 /sbin/mksnap_ffs
-r-sr-xr-- 2 root operator 15664 Aug 20 16:04 /sbin/poweroff
-r-sr-xr-- 2 root operator 15664 Aug 20 16:04 /sbin/shutdown
-r-sr-xr-- 1 root network 416200 Aug 20 16:05 /usr/sbin/ppp

[delphij]

These files do not by themselves contain sensitive information so we believed it doesn't hurt to allow world readability.