Make sure puppetserver packages are being built with JDK 8

It seems like the ezbake job building puppetserver master isn't using the JDK_AXIS }} param which we have set to {{oraclejdk8 - it seems to still be using openjdk7. https://jenkins-master-prod-1.delivery.puppetlabs.net/view/puppetserver/view/all/job/platform_puppetserver_packaging-os-clj_lein-ezbake_master/286/consoleFull

We should make sure it builds using jdk8. At the moment this may not cause problems, but once we have any java code in puppetserver that relies on jdk 8 it will be bad.

We should also remove the debian dependency on jdk 7 - https://github.com/puppetlabs/puppetserver/blob/master/resources/ext/ezbake.conf#L39 to ensure the puppetserver is installed with jdk 8.