kernel - do not wire user pages in sysctl

kernel - do not wire user pages in sysctl

* sysctl processes have not assumed that user pages would be wired
  for a long time.

* This also prevents sysctl from causing VM faults on the user memory
  after returning due to wiring changes.

  For example 'vmstat 1' no longer produces faults in the flt column
  generated by vmstat itself on every iteration.