symfony shell bug

2.2.0-RC2

if you start shell `php app/console -s`
and then print 

```
list --help
list
```

you will get error:

```
  [InvalidArgumentException]                              
  There are no commands defined in the "list" namespace.  

list [--xml] [--raw] [namespace]


The command terminated with an error status (1)
```
