Merge remote-tracking branch 'refs/remotes/origin/master' into develop

src/database/mongo/hash.js

@@ -279,7 +279,7 @@ module.exports = function (db, module) {
 		callback = callback || helpers.noop;
 		value = parseInt(value, 10);
 		if (!key || isNaN(value)) {
-			return callback();
+			return callback(null, null);
 		}
 
 		var data = {};