This PR Adds CentOS 7 support for Swift.
The following was required to get CentOS 7 to work:
* Add yum install path + packages
* Variablize rsync service name
* Gather network interface facts prior to setting storage/repl IPs
* Ensure /etc/defaults/rsync is only set for apt installations.
* Ensure the rsyslog service is started and enabled.
Change-Id: Ibaf8bc8d54b55820e8b527b52940c61c05c732d8