tests: test with the latest ansible stable-2.2 branch from github

Signed-off-by: Andrew Schoen <aschoen@redhat.com>

tox.ini

@@ -6,6 +6,7 @@ skipsdist = True
 whitelist_externals =
     vagrant
     bash
+    pip
 passenv=*
 setenv=
   ANSIBLE_SSH_ARGS = -F {changedir}/vagrant_ssh_config
@@ -34,6 +35,9 @@ changedir=
   # creates a cluster, purges the cluster and then brings the cluster back up
   purge_cluster_collocated: {toxinidir}/tests/functional/centos/7/journal-collocation
 commands=
+  # install latest stable version of ansible 2.2 from github, this can be removed
+  # when there is a release > 2.2.1.0
+  ansible2.2: pip install --upgrade git+git://github.com/ansible/ansible.git@stable-2.2
   vagrant up --no-provision {posargs:--provider=virtualbox}
   bash {toxinidir}/tests/scripts/generate_ssh_config.sh {changedir}