Don't restart event handler on termination

COUCHDB-2561
diff --git a/src/ioq.erl b/src/ioq.erl
index c4b3b4e..967a49b 100644
--- a/src/ioq.erl
+++ b/src/ioq.erl
@@ -91,6 +91,7 @@
 handle_config_change(_, _, _, _, _) ->
     {ok, nil}.
 
+handle_config_terminate(_, stop, _) -> ok;
 handle_config_terminate(_, _, _) ->
     spawn(fun() ->
         timer:sleep(5000),