machine_test.go: skip if we are not root
machine_test.go: skip if we are not root

Otherwise, the test ends in a panic.

TODO: remove all uses of panic in this code.

Signed-off-by: Ronald G. Minnich <f569d0af9a3481c4007b95c7180d6c41009f2513@gmail.com>

bobuhiro11/gokvm,bobuhiro11/gokvm