Readme: added blurb about host key checking
Fedora: updates to get ansible working in Fedora env
Roles: update directory structure
Packstack: tested RHEL/Fedora

* added playpen script to cleanup to get test machine in a clean state
* added workarounds for RHEL iptables issue
* moved python-httplib2 out of common and into role/linux/$os
  * due to epel
* other bug fix
Playbook: move to root of repo
Tempest: add tempest role