private boolean removeOlderThan(long days) {
        boolean action = false;
        long now = System.currentTimeMillis();
        for (LogFile lf : knownFiles) {
            if (olderThan(lf, days, now)) {
                lf.path.delete();
                log.info("Deleted: "+lf.path);
                action = true;
            }
        }
        return action;
    }
Creates an instance of FilesArchive managing the given directory
logserver/src/main/java/com/yahoo/logserver/handlers/archive/FilesArchived.java