Rudder

Sometimes, for some unknown reasons, promises get corrupted (files are not there) on the node.

A workaround to restore the situation is to add a step in check_rudder_agent script that would:
- check if failsafe.cf, promises.cf and common/1.0/update.cf are there and non empty
- if they are there, do nothing
- if not, copy from /opt/rudder/share/initial-promises to /var/rudder/cfengine-community/inputs, and execute then cf-agent -Kf failsafe.cf && cf-agent

• if any of these file is empty, nothing can work at all
• running cf-promises can be ressource intensive, so running it always is not a so great idea
• if these files are empty, then the failsafe has just be run, so the -K is mandatory. The cf-agent was not run recently (valid promises are more than 5 minutes old), so no need of -K for that