Add rhel7-extras repo.

Several pythong packages (flask/itsdangerous) moved from epel to
the rhel7 extra's repo.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>
Use Seperate rhel6-server/optional repos.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>
Merge branch 'master' of github.com:ceph/ceph-qa-chef