minor cleanup

src/categories.js

@@ -304,7 +304,7 @@ var db = require('./database'),
 			}
 			callback(null, categories);
 		});
-	}
+	};
 
 	Categories.getCategoryField = function(cid, field, callback) {
 		db.getObjectField('category:' + cid, field, callback);

src/database/redis.js

@@ -223,7 +223,7 @@
 	module.getObjectFields = function(key, fields, callback) {
 		redisClient.hmget(key, fields, function(err, data) {
 			if(err) {
-				return callback(err, null);
+				return callback(err);
 			}
 
 			var returnData = {};

src/socket.io/topics.js

@@ -261,9 +261,7 @@ SocketTopics.loadMore = function(socket, data, callback) {
 			privileges: function(next) {
 				threadTools.privileges(data.tid, socket.uid, next);
 			}
-		}, function(err, results) {
-			callback(err, results);
-		});
+		}, callback);
 	});
 };