support ubuntu16 hdp-utils repo

When using HDP, the repos recipe does not include ubuntu16 in its os determination, and as a result configures the hdp.utils repo using ubuntu12. This causes problems with snappy.

We are currenly using the 1.1.0.20 version of the repo, which does not contain ubuntu16. 1.1.0.21 does have ubuntu16, however interestingly appears to contain libsnappy1 instead of the xenial-equivalent libsnappy1v5. more research may be needed.