add spec for undeploy step
add spec for undeploy step

Change-Id: I872107f94df58a28267ffe120e17dd4756a320ac

cloudfoundry-incubator/bosh-vcloud-cpi-release,wcamarao/bosh-vcloud-cpi-release,wcamarao/bosh-vcloud-cpi-release,wcamarao/bosh-vcloud-cpi-release,cloudfoundry-incubator/bosh-vcloud-cpi-release,cloudfoundry-incubator/bosh-vcloud-cpi-release