fix log printing in QUnit

Author: hagaii

lib/server.js

@@ -349,7 +349,11 @@ exports.Server = function Server(bsClient, workers, config, callback) {
     },
     '_log': function logHandler(uri, body, request, response) {
       var uuid = getWorkerUuid(request);
-      var query = body;
+      var query = null;
+      try {
+        query = CircularJSON.parse(body);
+      } catch (e) {}
+      
       logger.trace('[%s] _log', ((uuid && workers[uuid]) || {}).id, query);
 
       var logged = false;