Document E125 as a won't fix.

As per the discussion in https://review.openstack.org/#/c/36788/ the
tempest team does not want to use E125 until
https://github.com/jcrocholl/pep8/issues/126 is  resolved.

Change-Id: I124e6f14db81d030a470ef3e73a33b15e9dea9ef
diff --git a/tox.ini b/tox.ini
index 04b845a..346f8ca 100644
--- a/tox.ini
+++ b/tox.ini
@@ -78,6 +78,7 @@
 local-check-factory = tempest.hacking.checks.factory
 
 [flake8]
+# E125 is a won't fix until https://github.com/jcrocholl/pep8/issues/126 is resolved.  For further detail see https://review.openstack.org/#/c/36788/
 ignore = E125,H302,H404
 show-source = True
 exclude = .git,.venv,.tox,dist,doc,openstack,*egg