Merge pull request #17 from sthaha/fix/virtenv-installation

tempest: fix virtenv installation
Foreman playbook now uses foreman_nodes as a variable passed to get_nodes
Add tags to foreman playbook
Add support for using a specific RDO repo
Tweak tags. Remove foreman tag, since that doesn't really make sense
tempest: testr skip list
Merge pull request #19 from gabrielecerami/testr_skip_list_squashed

tempest: testr skip list