Allow raw and script to support su

Currently, su support does not extend to `raw` and `script`.

`ansible 1.6 (devel ae1b183855) last updated 2014/03/28 16:45:19 (GMT -500)`

##### Current functionality:

```
ansible all -i test.sivel.net, --su --ask-su-pass -m raw -a whoami
test.sivel.net | success | rc=0 >>
matt
```

```
ansible all -i test.sivel.net, --su --ask-su-pass -m script -a ./whoami.sh
test.sivel.net | success | rc=0 >> {
    "changed": true,
    "rc": 0,
    "stderr": "",
    "stdout": "matt\r\n"
}
```

##### After:

```
ansible all -i test.sivel.net, --su --ask-su-pass -m raw -a whoami
test.sivel.net | success | rc=0 >>
root
```

```
ansible all -i test.sivel.net, --su --ask-su-pass -m script -a ./whoami.sh
test.sivel.net | success | rc=0 >> {
    "changed": true,
    "rc": 0,
    "stderr": "",
    "stdout": "root\r\n"
}
```

Additionally, I found a "bug" in logic of `raw.py` for stripping the `SUDO-SUCCESS-` string.  As such the string was not being removed from the output.  I've adjusted the logic and regular expression there as well to properly remove the string.  It seems stdout did not start with `SUDO-SUCCESS-` it was actually `\r\nSUDO-SUCCESS-`.