Cleared up the last remaining pylint problems.

The trailing whitespace was easy, but the no-value-for-parameter
messages have been escalated to the Pylint team as
https://bitbucket.org/logilab/pylint.org/issue/6/false-positive.
diff --git a/app/soc/models/conversation.py b/app/soc/models/conversation.py
index 3a09410..7b62f86 100644
--- a/app/soc/models/conversation.py
+++ b/app/soc/models/conversation.py
@@ -92,7 +92,7 @@
   In addition to being a record of a user's involvement in a conversation, it
   stores the time of the last message seen by the user, and it also store's the
   user's preferences for this conversation.
-  
+
   Parent:
     soc.models.conversation.Conversation
   """
diff --git a/app/soc/modules/gci/views/conversation.py b/app/soc/modules/gci/views/conversation.py
index 2d7dea4..6de52fb 100644
--- a/app/soc/modules/gci/views/conversation.py
+++ b/app/soc/modules/gci/views/conversation.py
@@ -286,7 +286,10 @@
 
     conv_user_key = conv_user.key
 
-    @ndb.transactional(xg=True)
+    # TODO(nathaniel): Remove the suppression on the following line when
+    # https://bitbucket.org/logilab/pylint.org/issue/6/false-positive-no
+    # is fixed.
+    @ndb.transactional(xg=True)  # pylint: disable=no-value-for-parameter
     def set_notifications_enabled_txn():
       # transactionally get latest GCIConversationUser
       conv_user = conv_user_key.get()