Use deepMerge in deepMerge

lib/utils.js

@@ -272,9 +272,9 @@ function deepMerge(/* obj1, obj2, obj3, ... */) {
   var result = {};
   function assignValue(val, key) {
     if (typeof result[key] === 'object' && typeof val === 'object') {
-      result[key] = merge(result[key], val);
+      result[key] = deepMerge(result[key], val);
     } else if (typeof val === 'object') {
-      result[key] = merge({}, val);
+      result[key] = deepMerge({}, val);
     } else {
       result[key] = val;
     }