fix where parser=future caused "This Array Expression is not productive"

Enabling [parser=future](https://docs.puppetlabs.com/puppet/3/reference/experiments_future.html#enabling-the-future-parser) caused:

`Error: Could not retrieve catalog from remote server: Error 400 on SERVER: This Array Expression is not productive. A Host Class Definition can not end with a non productive construct at /etc/puppet/modules/keepalived/manifests/init.pp:35:9 on node admin022
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run`