Follow the same process of root device selection as in IPA
which changed in https://review.opendev.org/c/openstack/ironic-python-agent/+/850861
The change introduces 'skip_block_devices' field into properties which
contains a list of hints pointing to devices that cannot be root devices
Change-Id: I94c8607ef9c610eadf1b5bce4fb154e97939a643