Constant error fixed

Fixes these errors:

antonio@tron:~/src/api.legendas.tv/examples$ ./legendas_dir.php /home/antonio/Downloads/Torrents/
PHP Notice:  Constant TORRENTDIR already defined in /home/antonio/src/api.legendas.tv/examples/legendas_dir.php on line 6
PHP Warning:  scandir(): Directory name cannot be empty in /home/antonio/src/api.legendas.tv/examples/legendas_dir.php on line 12
PHP Warning:  Invalid argument supplied for foreach() in /home/antonio/src/api.legendas.tv/examples/legendas_dir.php on line 14

PS: Tested in Ubuntu 12.04 LTS