Link /usr/bin/cpuset to a relative path

[ngie]

Summary

This creates an appropriate symlink instead of a potentially incorrect
path.

MFC after: 2 weeks
Requested by: imp

Test Plan

Confirmed cpuset continued to work after the change:

$ ls -l /usr/bin/cpuset
lrwxr-xr-x  1 root wheel 16 Aug 10 18:09 /usr/bin/cpuset -> ../../bin/cpuset
$ /usr/bin/cpuset true
$ sudo /usr/bin/cpuset -g -p 1 
pid 1 mask: 0, 1, 2, 3, 4, 5
pid 1 domain policy: first-touch mask: 0
$

[kevans]

Whoops- good point...