kernel - Remove ad-hoc increment/decrement of vm->vm_sysref

kernel - Remove ad-hoc increment/decrement of vm->vm_sysref

* Remove the ad-hoc increment/decrement of vm->vm_sysref when pulling data
  out for a ps.  Acquire p->p_token instead.

  This is an attempt to determine whether these adhoc operations are
  responsible for causing a race that results in the seg-fault issue we
  see on monster.