Rudder

As reported by Alex in #4498, the init script is too eager in its agent killing

                # Presence of PID file
                # If the pid file is not readable or is empty, kill all process by name
                if [ ! -r ${CFENGINE_COMMUNITY_PID_FILE[$daemon]} -o ! -s ${CFENGINE_COMMUNITY_PID_FILE[$daemon]} ]
                then
                        # Try a killall
                        /usr/bin/killall -KILL ${CFENGINE_COMMUNITY_BIN[$daemon]}

On a openvz system, it would simply wipe all the daemon running

We should implement a similar fix as in http://www.rudder-project.org/redmine/issues/3928 / https://github.com/Normation/rudder-packages/pull/211/files to detect if its a VZ system, and kill only the relevant deamon

(as vzps.py is present only in 2.8, i'm targeting this ticket to 2.8)