Enforce check F821 and H304

The F821 "undefined name" rule wasn't enforced as it should be. This
is an important one since undefined names raise exceptions.

The H304 "no relative imports" also wasn't enforced.

Change-Id: If7fb6705c916b6df389590c9a48696e8850f328b

1 files changed, 1 insertions, 3 deletions

diff --git a/tox.ini b/tox.ini
index 1a69e3b..1ee9320 100644
--- a/tox.ini
+++ b/tox.ini
@@ -32,10 +32,8 @@ downloadcache = ~/cache/pip
 commands = oslo_debug_helper {posargs}
 
 [flake8]
-# F821: undefined name
-# H304: no relative imports
 # H405: multi line docstring summary not separated with an empty line
-ignore = F821,H304,H405
+ignore = H405
 show-source = True
 exclude = .venv,.tox,dist,doc,*egg,build,*openstack/common*