Extend mandatory Flake8 cleanness

With the wider Flake8 run clean, this commit makes it mandatory and
removes the redundant narrower Flake8 call on the whitelist, removing
the now useless whitelist.

Reviewed By: tnfchris

Differential Revision: https://reviews.llvm.org/D94842

Author: Thomas Preud'homme

tox.ini

@@ -1,14 +1,3 @@
-[base]
-
-# Files we'd like to keep lint clean. Lets hope we can expand this list.
-whitelist_files = ./setup.py
-    ./deployment/
-    ./lnt/formats/
-    ./lnt/util/
-                  ./lnt/tests/
-                  ./lnt/testing/
-    ./tests/server/ui/
-
 [tox]
 envlist = py27
           py3
@@ -41,10 +30,8 @@ deps =
     flake8
 
 commands =
-    # Still lots of problems.
-    - flake8 --statistics --exclude=./lnt/external/  ./lnt/ ./tests/ ./setup.py ./deployment/
-    # But lets keep the clean files clean.
-    flake8 {[base]whitelist_files}
+    # Lets keep the clean files clean.
+    flake8 --statistics --exclude=./lnt/external/  ./lnt/ ./tests/ ./setup.py ./deployment/
 
 [testenv:docs]
 skip_install = true