Need way to pin Chef version for omnibus install

Although it is possible to specify an alternate URL for the omnibus installer, there's no way to request installation of a particular version. The downloaded (install.sh) artifact from the URL takes a '-v VERSION' argument, but there's no way to pass that argument through the cc_chef cloud-init module.

Without any way to pin the version, I am doomed to see messages like this in the cloud-init output logs:

Downloading Chef for ubuntu...
downloading https://www.chef.io/chef/metadata?v=&prerelease=false&nightlies=false&p=ubuntu&pv=14.04&m=x86_64
  to file /tmp/install.sh.1243/metadata.txt
trying wget...
url https://opscode-omnibus-packages.s3.amazonaws.com/ubuntu/10.04/x86_64/chef_12.3.0-1_amd64.deb
md5 d8421c9b3010deb03e713ada00387e8a
sha256 e06eb748e44d0a323f4334aececdf3c2c74d2f97323678ad3a43c33ac32b4f81
downloaded metadata file looks valid...
downloading https://opscode-omnibus-packages.s3.amazonaws.com/ubuntu/10.04/x86_64/chef_12.3.0-1_amd64.deb
  to file /tmp/install.sh.1243/chef_12.3.0-1_amd64.deb
trying wget...
Comparing checksum with sha256sum...

WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING

You are installing an omnibus package without a version pin. If you are installing
on production servers via an automated process this is DANGEROUS and you will
be upgraded without warning on new releases, even to new major releases.
Letting the version float is only appropriate in desktop, test, development or
CI/CD environments.

WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING

Installing Chef
installing with dpkg...
...