Fix error in Ubuntu 13.04

After upgrading to Ubuntu 13.04 phpsh was broken, you can see an example of the error here.

This pull request fixes the problem.

``` bash
Starting php
type 'h' or 'help' to see instructions & features
php> $foo = 'bar';

subprocess died with return code: 0
PHP died. Restarting php
``` 
 
SO info:
``` bash
uname --all
Linux *****-p6704es 3.8.0-19-generic #29-Ubuntu SMP Wed Apr 17 18:16:28 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
``` 
 
Python version
``` bash
python --version
Python 2.7.4
``` 

Php version
``` bash
php -v
PHP 5.4.9-4ubuntu2 (cli) (built: Mar 11 2013 16:09:26) 
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
```