(maint) Add java 8 as travis target
(maint) Add java 8 as travis target

Given that some of our packages now require java 8, it seems like a good idea
to add travis for it.

Alas, travis only has oraclejdk8 as a target, not openjdk8. :|

erikPrime/puppet-server,ahpook/puppet-server,cgvarela/puppet-server,shrug/puppet-server,rlinehan/puppetserver,briancain/puppet-server,camlow325/puppet-server,waynr/puppet-server,ahpook/puppet-server,rlinehan/puppet-server,rlinehan/puppetserver,cgvarela/puppet-server,waynr/puppet-server,rlinehan/puppet-server,rlinehan/puppetserver,puppetlabs/puppetserver,puppetlabs/puppetserver,camlow325/puppetserver,rlinehan/puppetserver,waynr/puppetserver,rlinehan/puppet-server,waynr/puppetserver,er0ck/puppetserver,camlow325/puppetserver,puppetlabs/puppetserver,erikPrime/puppetserver,cprice404/puppetserver,camlow325/puppetserver,fpringvaldsen/puppet-server,cprice404/puppet-server,puppetlabs/puppet-server,kylog/puppet-server,briancain/puppet-server,kylog/puppet-server,erikPrime/puppetserver,er0ck/puppetserver,cprice404/puppet-server,er0ck/puppetserver,cprice404/puppetserver,erikPrime/puppetserver,er0ck/puppetserver,shrug/puppet-server,waynr/puppetserver,shrug/puppet-server,briancain/puppet-server,ahpook/puppet-server,puppetlabs/puppet-server,camlow325/puppet-server,camlow325/puppetserver,kylog/puppet-server,waynr/puppet-server,fpringvaldsen/puppet-server,erikPrime/puppet-server,erikPrime/puppet-server,fpringvaldsen/puppet-server,camlow325/puppet-server,puppetlabs/puppet-server,cprice404/puppetserver,shrug/puppet-server,cgvarela/puppet-server,puppetlabs/puppetserver,cprice404/puppet-server