[docs] Fix root-user-create call
[docs] Fix root-user-create call

This fixes:

```
flag provided but not defined: --config
Usage of tsuru flags:
-h, --help  (= false)
    Display help and exit
-v, --verbosity  (= 0)
    Verbosity level: 1 => print HTTP requests; 2 => print HTTP requests/responses
--version  (= false)
    Print version and exit
```
tsuru/tsuru,ggarnier/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,guilhermebr/tsuru,gwmoura/tsuru,guilhermebr/tsuru,ggarnier/tsuru,cezarsa/tsuru,gwmoura/tsuru,cezarsa/tsuru,tsuru/tsuru,gwmoura/tsuru,tsuru/tsuru,tsuru/tsuru,ArxdSilva/tsuru,cezarsa/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,cezarsa/tsuru