Add a seed file for the Ceph barclamp.

In Rails 4, we need to do barclamp imports as part of seeding the
databases, not as part of the migration.
Fix up mon.rb to reflect that network is no longer its own barclamp.
Add CentOS and Redhat upstream repos for Ceph, and use Emperor.
On Centos and Redhat, we need ceph-debuginfo, not ceph-debug.