Newer versions of vagrant + older versions of centos were not playing well together due to the way number of ssh sessions were being managed. Hardcoded the number for that specific kitchen-test configuration.
The regex for 1.x agents did not appear to work as written. Basically if someone pinned an agent to be a 1.x version, the package would never be found because the underlying install command would've been asking for agent instead of threatstack-agent.
To describe the problems solved:
agentinstead ofthreatstack-agent.