exclude containers based on busybox from cleanup

containers based on busybox are used to create storage volumes.  When busybox
containers are removed, the data can become inaccessible depending on the
release process.

AWS-196

files/docker-rotate

@@ -3,5 +3,6 @@
 # Remove docker images keeping the last 3 of each type
 docker-rotate images --keep 3
 # Remove docker containers that have exited over an hour ago
-# and were created over a day ago
-docker-rotate containers --exited 1h --created 1d
+# and were created over a day ago>  Exclude containers based on busybox
+# which are typically used for data volumes.
+docker-rotate containers --exited 1h --created 1d --images ~busybox