Added a virtual package for repo only slaves

jenkins-debian-glue is the base package containing all required scripts
 - jenkins-debian-glue-repoenv  - virtual package for repo only slaves
 - jenkins-debian-glue-buildenv - virtual package for build only slaves
Merge branch 'master' of https://github.com/bmiklautz/jenkins-debian-glue

https://github.com/mika/jenkins-debian-glue/pull/75