Add ability to create empty disk images

[dcritch]

Is this a BUG REPORT or FEATURE REQUEST?:

/kind enhancement

What happened: I've been working with a combination of CNV, glusterfs and PXE. I've been creating VMs to PXE boot from a Satellite server to be provisioned. I've been using CDI to import a blank disk image from a URL.

What you expected to happen: Would it be possible for CDI to have an option to create empty/blank disks rather than import an existing image?

How to reproduce it (as minimally and precisely as possible): n/a Anything else we need to know?:

Environment:

• CDI version (use kubectl get deployments cdi-deployment -o yaml): n/a. using kubevirtci/disk-importer
• Kubernetes version (use kubectl version): Client Version: version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.0+d4cacc0", GitCommit:"d4cacc0", GitTreeState:"clean", BuildDate:"2018-09-26T12:30:09Z", GoVersion:"go1.10.2", Compiler:"gc", Platform:"linux/amd64"} Server Version: version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.0+d4cacc0", GitCommit:"d4cacc0", GitTreeState:"clean", BuildDate:"2018-09-26T12:30:09Z", GoVersion:"go1.10.2", Compiler:"gc", Platform:"linux/amd64"}
• Cloud provider or hardware configuration: bare metal PowerEdge servers
• Install tools: openshift-ansible, cnv installed directly from manifest

[zvikorn]

yes. I have started working on this today.

[dcritch]

Awesome! Looking forward to the feature.

[zvikorn]

Please do NOT merge until #502 is merged. This PR will have to be rebased.