Append .log to file writer filenames

Use a .log suffix for filenames generated by the file writer.

Improve error handling in the CLI.
Rebalancing tests
Updating cartridge versions
Merge pull request #4906 from ironcladlou/logshifter/filenames

Merged by openshift-bot
Merge pull request #4910 from jhadvig/latest_versions_master

Merged by openshift-bot
Merge pull request #4908 from danmcp/master

Merged by openshift-bot
Use NodeLogger in MCollective agent code

Send log messages originating from the MCollective agent to
NodeLogger, as these logs are considered platform events.

Only things related to MCollective internals and the agent API should
flow into the MCollective log.
Merge pull request #4843 from ironcladlou/logging/agent

Merged by openshift-bot