Fix flake8 H404 errors

Fix H404 error and start enforcing it.

Trivialfix

Change-Id: I0c062733660031faf43838798a697daf6674ef14
diff --git a/neutron_tempest_plugin/api/base.py b/neutron_tempest_plugin/api/base.py
index df0f4fa..c4bc71d 100644
--- a/neutron_tempest_plugin/api/base.py
+++ b/neutron_tempest_plugin/api/base.py
@@ -34,8 +34,7 @@
 
 class BaseNetworkTest(test.BaseTestCase):
 
-    """
-    Base class for the Neutron tests that use the Tempest Neutron REST client
+    """Base class for Neutron tests that use the Tempest Neutron REST client
 
     Per the Neutron API Guide, API v1.x was removed from the source code tree
     (docs.openstack.org/api/openstack-network/2.0/content/Overview-d1e71.html)