Use flake8/hacking instead of pep8/pyflakes.

Change-Id: Id0e447a7e66562d6ad0298619e36f752ae31adb0
Reviewed-on: https://review.openstack.org/33349
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
diff --git a/tox.ini b/tox.ini
index 0d49693..dea7c57 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,9 +13,7 @@
 downloadcache = ~/cache/pip
 
 [testenv:pep8]
-deps = pep8==1.3.3
-       -r{toxinidir}/tools/pip-requires
-commands = pep8 --ignore=E123,E125,E128 --repeat --show-source --exclude=.venv,.tox,dist,doc,build .
+commands = flake8
 
 [testenv:cover]
 setenv = NOSE_WITH_COVERAGE=1
@@ -30,3 +28,8 @@
 
 [testenv:validate-layout]
 commands = zuul-server -c etc/zuul.conf-sample -t -l {posargs}
+
+[flake8]
+ignore = E123,E125,E128,H
+show-source = True
+exclude = .venv,.tox,dist,doc,build,*.egg