Removed all validate-contents tests from pep8 test

Change-Id: I2762ecf64fab090f3594bf4330dea101ba1434dd
Partially-Implements: blueprint rename-pep8-validate

tox.ini

@@ -10,11 +10,6 @@ deps = -r{toxinidir}/requirements.txt
 
 [testenv:pep8]
 commands =
-    {toxinidir}/tools/validate-all-json.sh
-    {toxinidir}/tools/validate-all-yaml.sh
-    {toxinidir}/tools/validate-all-maintainer.sh
-    {toxinidir}/tools/validate-links.sh
-    {toxinidir}/tools/validate-min-env-vars.sh
     flake8
 
 [testenv:validate-contents]