Fix #321 - root_user should be setup before configuring backup user

Otherwise puppet might try to setup the backup user even before
the service is running and will fail.
Use https url to make puppet-librarian more proxy-friendly

For people in restricted networks it's quite common to not
be able to use git:// urls, but https-urls work through proxies.
Merge pull request #400 from duritong/fix_backupuser_dependency

Fix backupuser dependency