Fix toxfile

tox.ini

@@ -1,9 +1,4 @@
 [tox]
-envlist =
-    es, addons, devhub, files, main, ui-tests, docs, assets
-    amo-lib-locales-and-signin,
-    reviewers-and-zadmin,
-    accounts-users-and-ratings,
 envlist =
     es, devhub, main, ui-tests, docs, assets,
     addons-versions-and-files,
@@ -96,13 +91,13 @@ commands =
 [testenv:py2-codestyle]
 recreate = True
 commands =
-    pip install -r requirements/flake8_py2.txt
+    pip install -r requirements/flake8.txt -r requirements/flake8_py2.txt
     make flake8
 
 [testenv:py3-codestyle]
 recreate = True
 commands =
-    pip install -r requirements/flake8_py3.txt
+    pip install -r requirements/flake8.txt
     make flake8
 
 [testenv:docs]