Currently devstack create VMs and then deploy Ironic on these VMs.
Sometimes developer may want to deploy on real platform.
A separated file is required to provide the baremetal compute node
information, which includes four fields for each hardware platform,
the ipmi address, the mac address, the ipmi user name and the
password.
Change-Id: I422b43eae6edc95f15b8c40383d0ba7fbcd9b1ff