Separate RHEL from Ubuntu code and fix Ubuntu ceph default repo url.
Separate RHEL from Ubuntu code and fix Ubuntu ceph default repo url.

The ceph repo for Ubunto was broken and pointed to
http://mirror.centos.org/centos/7/storage/x86_64/ceph-jewel/dists/xenial/main/binary-amd64/Packages
[1].

Furthermore epel activation/deactivation makes no sense on Ubuntu
platform.

[1] http://logs.openstack.org/65/432165/19/check/gate-puppet-vswitch-puppet-beaker-rspec-ubuntu-xenial/daad266/console.html#_2017-04-03_05_13_45_306095

Closes-Bug: #1678932

Change-Id: I5d3c75b14145d3f55eec5f019b962cc4888404e5

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration