Correct reference to deploy_image variable in install playbook
Correct reference to deploy_image variable in install playbook

The install playbook was creating an incorrectly-named image.
Fix the reference to the variable so that the image is named
correctly.

Depends-On: Ica0879b7b6c3bdbf7a520a6e746b5d1cc670fe61
Change-Id: Ib7e7920fafe18ec64211c02e54e734ad874cc236
Closes-Bug: 1478970

bcornec/bifrost,bcornec/bifrost,openstack/bifrost,devananda/bifrost,devananda/bifrost,openstack/bifrost,EntropyWorks/bifrost,EntropyWorks/bifrost