Do not save task.message in action logs

task.message is not saved in action logs now.
Key "additional_info.message" is kept to keep compatibility with
current validation and migration in collector.
Test added.

Change-Id: Ia85d6f4668b9be94480bd07d78fe968a805f0f97
Closes-Bug: #1401572
Merge "Do not save task.message in action logs"