Amend flatten function to accomodate for a bugg in UnderscoreJS.

using .each on an object with a property called length will break UnderscoreJS

Author: stijnbernards

lib/web/mage/utils/objects.js

@@ -148,7 +148,18 @@ define([
             separator = separator || '.';
             result = result || {};
 
-            _.each(data, function (node, name) {
+            if(!data) {
+                return result;
+            }
+
+            // UnderscoreJS each breaks when an object has a length property so we use Object.keys
+            _.each(Object.keys(data), function (name) {
+                var node = data[name];
+
+                if ({}.toString.call(node) === '[object Function]') {
+                    return;
+                }
+
                 if (parent) {
                     name = parent + separator + name;
                 }
@@ -436,3 +447,4 @@ define([
         }
     };
 });
+