updated bind method to stop un-needed variable assignment when using native method.

underscore.js

@@ -409,8 +409,8 @@
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
   _.bind = function(func, obj) {
-    var args = slice.call(arguments, 2);
     if(nativeBind && func.bind === nativeBind) return FuncProto.bind.apply(func, slice.call(arguments, 1));
+    var args = slice.call(arguments, 2);
     return function() {
       return func.apply(obj || {}, args.concat(slice.call(arguments)));
     };