Remove H803 of flake8 ignore list in tox

In hacking >=0.10.0,there is not H803,we should remove it.

Change-Id: Ie290e66824efee3f302b97d7f0418b3b18ede5e1

tox.ini

@@ -28,10 +28,9 @@ commands = python setup.py build_sphinx
 commands = oslo_debug_helper -t toscaparser/tests {posargs}
 
 [flake8]
-# H803 skipped on purpose per list discussion.
 # E123, E125 skipped as they are invalid PEP-8.
 
 show-source = True
-ignore = E123,E125,H803
+ignore = E123,E125
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build