Packstack AIO: launch instance and install/test in openstack env

* Had to duplicate part of the get_nodes role for now
* Had to duplicate part of the set_facts
Fix /etc/hosts generation
Merge pull request #11 from weshayutin/aio_neutron_update

Updates to install packstack and launch tempest
tempest: install venv script
tempest: pip conf to cache downloads
tempest: openstack-setup task
tempest: task to setup tempest
tempest: stores test config in vars
tempest: parameterizes tempest_init.pp
tempest: script to setup tempest
tempest: task to setup tempest
tempest: script to run nosetest/testr
Refactors tempest role to sub-tasks
tempest: adds TODO/NOTES to config
tempest: minor updates to usage section of run_tempest.sh
tempest: run_tempest.sh ignore test run failure
Merge pull request #13 from weshayutin/tempest_update2

Tempest update2
Refactor get_nodes and set_facts into a single role
tempest: correct typo in exclude list
tempest: adds files to exclude list