Add tox -eansible-lint

Currently, just run /bin/true until we actually have some playbooks
installed.

Change-Id: I62c5aafea8fa71fd64809ce8b5650dcfdaf51f8d
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

test-requirements.txt

@@ -1,2 +1,3 @@
 hacking<0.11,>=0.10
+ansible-lint
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3

tox.ini

@@ -1,12 +1,19 @@
 [tox]
 minversion = 1.4.2
-envlist = docs,pep8
+envlist = ansible-lint,docs,pep8
 skipsdist = True
 
 [testenv]
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 
+[testenv:ansible-lint]
+setenv =
+  ANSIBLE_CONFIG = tests/ansible.cfg
+whitelist_externals = bash
+# NOTE(pabelanger): Place holder until we add ansible playbooks
+commands = /bin/true
+
 [testenv:docs]
 commands = python setup.py build_sphinx