Replaced the _kern_null syscall with _kern_is_computer_on.
is_computer_on_fire is a bit harder, since it returns a float from kernelland, which
at the moment isn't supported in haiku.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20069 a95241bf-73f2-0310-859d-f6bbb57e9c96