Comment 17 for bug 937352

There is a lot of confusing information in the above comments.
To sum up the solution that I'll be uploading shortly, for precise we did:
 * add to cloud-initramfs-growroot a 'udevadm settle' before invoking growpart to apply the change. This ensures that any disk events for the root block device are finished before sfdisk is run.
 * in cloud-utils's growpart, use '--no-reread' argument to sfdisk when making changes to the disk.