new: [docker-host] added ``docker-clean` in cron's daily tasks

precise/host/hooks/install.d/70-0k.sh

@@ -135,6 +135,7 @@ mkdir -p /opt/apps
     fi
 
     ln -sfn /opt/apps/0k-docker/bin/* /usr/local/sbin/
+    ln -sfn /opt/apps/0k-docker/bin/docker-clean /etc/cron.daily/docker-clean
     ## in update, will remove broken links to binaries that were removed
     find -L /usr/local/sbin -maxdepth 1 -type l -delete
 )