src: remove unused comment

Now that Context::New(Isolate*) returns Local, the removed comment is
no longer applicable that there is a Persistent which will need to be
disposed.

src/node_script.cc

@@ -382,10 +382,6 @@ Handle<Value> WrappedScript::EvalMachine(const Arguments& args) {
   Local<Array> keys;
   if (context_flag == newContext) {
     // Create the new context
-    // Context::New returns a Persistent<Context>, but we only need it for this
-    // function. Here we grab a temporary handle to the new context, assign it
-    // to a local handle, and then dispose the persistent handle. This ensures
-    // that when this function exits the context will be disposed.
     context = Context::New(node_isolate);
 
   } else if (context_flag == userContext) {