Update flake8 ignore list

In hacking > 0.10.0, there is no E123 and E125, so this commit to
delete them.

Change-Id: I66f53f46337d4206a269f2e09822bf31d8433edf

tox.ini

@@ -39,10 +39,8 @@ commands = python setup.py build_sphinx
 
 [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 = H803
 builtins = _
 exclude=.venv,.git,.tox,dist,*openstack/common*,*lib/python*,*egg,build,*autogenerate_config_docs/venv,*autogenerate_config_docs/sources
 # 28 is currently the most complex thing we have