changing order of operations to force an errror when _.bind -ing null…

… or undefined values.

underscore.js

@@ -408,8 +408,9 @@
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
+  // We check for `func.bind` first, to fail fast when `func` is undefined.
   _.bind = function(func, obj) {
-    if (nativeBind && func.bind === nativeBind) return func.bind.apply(func, slice.call(arguments, 1));
+    if (func.bind === nativeBind && nativeBind) return func.bind.apply(func, slice.call(arguments, 1));
     var args = slice.call(arguments, 2);
     return function() {
       return func.apply(obj, args.concat(slice.call(arguments)));