Add doc/ to pep8 check

We had unused imports there, this would prevent us from letting more of
such errors in.

Change-Id: Ie78c18dd3b9ab34370e47eba98b32740e0c83e1d

doc/source/conf.py

@@ -77,4 +77,4 @@ latex_documents = [
 ]
 
 # Example configuration for intersphinx: refer to the Python standard library.
-#intersphinx_mapping = {'http://docs.python.org/': None}
+# intersphinx_mapping = {'http://docs.python.org/': None}

tox.ini

@@ -28,7 +28,7 @@ commands = python setup.py test --coverage --coverage-package-name=oslo_concurre
 [flake8]
 show-source = True
 ignore = H405
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+exclude=.venv,.git,.tox,dist,*lib/python*,*egg,build
 
 [hacking]
 import_exceptions =