Refreshes calling of ansible-lint

- Assure compatible version of Ansible is installed
- Make use of ability to detect roles and playbooks in linter, which
  also makes it execution ~9x faster.

Change-Id: Ife53d9f3161f6531102ed82f62f5d91c805e6cdc

test-requirements.txt

@@ -4,6 +4,7 @@
 
 hacking>=3.0,<3.1.0 # Apache-2.0
 
-ansible>=2.7.0,<2.8
-ansible-lint>=4,<=5
+# ansible-lint requires ansible>=2.9
+ansible>=2.9.0,<2.10
+ansible-lint>=4.3.6,<=5
 bashate>=0.2

tox.ini

@@ -32,11 +32,7 @@ setenv =
   ANSIBLE_LIBRARY= {toxinidir}/tests/fake-ansible
 commands =
   flake8 {posargs}
-  bash -c "find playbooks -type d -name "legacy" -prune -o \
-    -type f -regex '.*.y[a]ml' -print0 | xargs -t -n1 -0 \
-    ansible-lint"
-  bash -c 'find roles -maxdepth 1 -mindepth 1 -type d -printf "%p/\n" | \
-    xargs -t -n1 ansible-lint'
+  ansible-lint
   # Ansible Syntax Check
   bash -c "cd playbooks; find . -type f -regex '.*.y[a]?ml' -exec \
     ansible-playbook --syntax-check -i {toxinidir}/tests/inventory \{\} + > /dev/null"