If the local disk has already a partition table, it must be clean up
before the disk is exposed through iscsi. Otherwise this disk partition
can create a conflict during the grub installation.
How reproducible:
1. Inject an image on the root disk, like for example ipxe.usb or ipxe.iso
2. Try to deploy a system on the node using Ironic
3. The node is properly deployed but the grub installation has failed
with the following error:
attempting to install grub to a disk with multiple partition labels
A simple sgdisk -Z /dev/vdX is not enough because grub-install will
inspect the disk and will still detect a remaining partition.
This commit makes use of the ironic-lib to do the clean up of the disk.
The additional review Id59fa5a06b9115c0f9afc09aae95daaac97e2fac increase
the amount of data to wipe.
References:
https://bugzilla.redhat.com/show_bug.cgi?id=1310883
Partial-Bug: 1550604
Change-Id: Ie68cb6296c782e904d40f6e9de0faa52ab2af2bf
0b1f01db94