Fix flake8 H404 errors

Fix H404 error and start enforcing it.

Trivialfix

Change-Id: I0c062733660031faf43838798a697daf6674ef14
diff --git a/tox.ini b/tox.ini
index 5eb8b10..20a7deb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -57,10 +57,9 @@
 # E128 continuation line under-indented for visual indent
 # E129 visually indented line with same indent as next logical line
 # E265 block comment should start with '# '
-# H404 multi line docstring should start with a summary
 # H405 multi line docstring summary not separated with an empty line
 # N530 direct neutron imports not allowed
-ignore = E125,E126,E128,E129,E265,H404,H405,N530
+ignore = E125,E126,E128,E129,E265,H405,N530
 # H106: Don't put vim configuration in source files
 # H203: Use assertIs(Not)None to check for None
 # H904: Delay string interpolations at logging calls