Enable Non-Occurring Flake8 Errors

Flake8 currently ignores the following errors:
B301: Python3 does not include ".iter*" methods on dictionaries
H237: Module is removed in python3
W191: Indentation contains tabs
Which do not appear currently in the repo. Enable them
so that they do not get introduced

Change-Id: I0321ee40f869c03321a1cbd67c45056206437f6b
Story: 2004515
Task: 30076
Signed-off-by: Eric Barrett <eric.barrett@windriver.com>

tox.ini

@@ -47,11 +47,9 @@ commands =
 # H102 is apache license
 # H104: File contains nothing but comments
 # H201: no 'except:' at least use 'except Exception:'
-# H237: module exception is removed in Python 3
 # H238: old style class declaration, use new style
 # H306: imports not in alphabetical order
 # W series
-# W191 indentation contains tabs
 # W291 trailing whitespace
 # W391 blank line at end of file
 # W503 line break before binary operator
@@ -60,13 +58,12 @@ commands =
 # B007 Loop control variable 'cpu' not used within the loop body.
 # B009 Do not call getattr with a constant attribute value
 # B010 Do not call setattr with a constant attribute value
-# B301 Python 3 does not include `.iter*` methods on dictionaries.
 # F series
 # F401 'module' imported but unused
 ignore = E265,E266,E402,E501,E722
-         H101,H102,H104,H201,H238,H237,H306,
-         W191,W291,W391,W503,
-         B001,B007,B009,B010,B301,
+         H101,H102,H104,H201,H238,H306,
+         W291,W391,W503,
+         B001,B007,B009,B010,
          F401
 
 [testenv:pep8]