If the provided container image name includes a `/` character, the build
will fail when copying the OCI image to a tarball:
> + buildah push git.pyrocufflink.net/containerimages/build/selinux:dev-ci oci-archive:/home/jenkins/agent/workspace/ainerImages_build.selinux_dev_ci/build/selinux-amd64.tar
> Error: lstat /home/jenkins/agent/workspace/ainerImages_build.selinux_dev_ci/build: no such file or directory
To resolve this, we need to escape the image name when constructing the
path to the tar file.
Dustin C. Hatch
93da924aab