Both issues affect Train and earlier releases.
1. Fix monasca-grafana by pinning more Ruby gems
childprocess 3.0.0 and ffi 1.13.0 depend on Ruby 2.3.
2. Bump bifrost to 6.0.4
Bifrost had a fix to stop using the master branch of DIB which dropped
support for Python 2.
3. Drop docker-client from OracleLinux sensu-client image
The package fails to install due to a missing dependency on
(cherry picked from commit