Include a random device.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274739 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
* Add a random device
* Use the same rootdev path as MALTA, so the same emulator setups
  can be used with minimal fuss.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274740 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f