mranney/node_redis — pull request #403 by jifeng (2013-03-17 10:14:57+00:00)
Title: need not send message to server when set undefined value

now there is a problem when set undefined or null value, for example:

```
client.set('key', undefined, function (err) {
console.log(err);
client.get('key', function (err, item) {
console.log(typeof item, item);
});
});
```

result:
```
null
string undefined
```
the datatype is changed (undefined changed to string), and if value is invalid , client need not send message to server.