Send nailgun-agent logs to syslog as well

Partial blueprint: collect-mco-and-agent-logs-with-shotgun

Change-Id: I6bc16ddc39d970ae52a3cbeaf5531f0358a5b41d
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "Send nailgun-agent logs to syslog as well"