- In sys_setsockopt():

- In sys_setsockopt():
  o  Don't test sopt.sopt_val against NULL; this is not setup yet.  This fixes
     random setsockopt(2) failure with EINVAL.
  o  Clear sopt.sopt_val earlier
  o  Don't do copyout in setsockopt; the user arg is const
- In sys_getsockopt():
  o  Clear sopt.sopt_val earlier
  o  Centralize sopt.sopt_valsize check

Reviewed-by: aggelos@