Fix output image glob pattern for CloudStack image builds

[abhay-krishna]

Fix output image glob pattern for CloudStack image builds.

Example build output

==> Builds finished. The artifacts of successful builds are:

--> qemu: VM files in directory: ./output/rhel-8-kube-v1.28.1
--> qemu: VM files in directory: ./output/rhel-8-kube-v1.28.1
--> qemu: VM files in directory: ./output/rhel-8-kube-v1.28.1

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[abhay-krishna]

/approve

[eks-distro-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: abhay-krishna

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