Updated Omnibus with default package user/group fix
Ensure contents of install dir are owned by root
Remove hard dependency on `chef-server-core`

This matches the behavior on all other server add-ons.
Remove opscode-push-jobs-client

This project is now built out of:
https://github.com/opscode/omnibus-push-jobs-client
Merge pull request #63 from opscode/schisamo/package-uid-fix

Packaging fixes for Push Jobs Server