avoid relying on crazy monoid instance

This code worked as intended, but only by accident, because of this
instance:

instance Monoid b => Monoid (x -> b) where mempty = const (mempty :: b)

Let's be explicit that we throw away the error message.

Remote/List.hs

@@ -112,7 +112,8 @@ remoteGen m t g = do
 	let c = fromMaybe M.empty $ M.lookup cu m
 	pc <- if null c
 		then pure mempty
-		else either mempty id . parseRemoteConfig c <$> configParser t
+		else either (const mempty) id . parseRemoteConfig c
+			<$> configParser t
 	generate t g u pc gc rs >>= \case
 		Nothing -> return Nothing
 		Just r -> Just <$> adjustExportImport (adjustReadOnly (addHooks r)) rs