Make tox happy again after dropping lib_utils

tox.ini

@@ -1,8 +1,8 @@
 [tox]
 minversion=2.3.1
 envlist =
-    py{27,35}-{flake8,pylint,unit}
-    py27-{yamllint,ansible_syntax,generate_validation}
+    py{27,35}-{flake8,pylint}
+    py27-{yamllint,ansible_syntax}
 skipsdist=True
 skip_missing_interpreters=True