Fix H404/405 violations for common code

There is a lot of H404/405 violations in Tempest now, and that leads
difficult to migrate the code to tempest-lib or the other projects'
repos. This patch fixes these violations for common code.

Change-Id: I5ddedcdd4d00ddbd53e1006ba40dce447fba3c20
diff --git a/tempest/common/dynamic_creds.py b/tempest/common/dynamic_creds.py
index ae53543..e950c3e 100644
--- a/tempest/common/dynamic_creds.py
+++ b/tempest/common/dynamic_creds.py
@@ -72,9 +72,9 @@
             self.identity_admin_client, self.creds_domain_name)
 
     def _get_admin_clients(self):
-        """
-        Returns a tuple with instances of the following admin clients (in this
-        order):
+        """Returns a tuple with instances of the following admin clients
+
+        (in this order):
             identity
             network
         """