hack/build: Pin to RHCOS 47.297 and quay.io/openshift-release-dev/ocp-release:4.0.0-0.3#1192

wking wants to merge 2 commits intoopenshift:master-0.12.0openshift/installer:master-0.12.0from

wking:version-0.12.0-pinswking/openshift-installer:version-0.12.0-pinsCopy head branch name to clipboard