Use standard ansible-lint config file

Allows calling ansible-lint directly instead of hardcoding its
configuration inside tox.

This plays much better with other tools, like editors which may
perform the linting themselves.

Change-Id: I09e48322f11de33a2ce97a27cf7cf93225ccc12c

.ansible-lint

@@ -0,0 +1,5 @@
+---
+parseable: true
+skip_list:
+  # [ANSIBLE0012] Commands should not change things if nothing needs doing
+  - ANSIBLE0012

tox.ini

@@ -38,11 +38,10 @@ whitelist_externals = bash
 commands =
   flake8 {posargs}
   # Ansible lint
-  # [ANSIBLE0012] Commands should not change things if nothing needs doing
   bash -c "find playbooks -type f -regex '.*.ya?ml' -print0 | \
-    xargs -t -n1 -0 ansible-lint -xANSIBLE0012"
+    xargs -t -n1 -0 ansible-lint"
   bash -c 'find roles -maxdepth 1 -mindepth 1 -type d -printf "%p/\n" | \
-    xargs -t -n1 ansible-lint -xANSIBLE0012'
+    xargs -t -n1 ansible-lint'
   # Ansible Syntax Check
   bash -c "find playbooks -type f -regex '.*.ya?ml' -exec \
     ansible-playbook --syntax-check -i {toxinidir}/tests/inventory \