Fix for `$path_fix` when `sizeof($parts) == 1`

The result from the `explode` call will always be an array, never NULL,
so it doesn't make sense to check it using `isset`.
Remove uneccessary isset check

- added intval since it clarifies that an int is expected
- added curly braces since it's a good practice :)
Merge pull request #147 from scriptotek/master

Fix for `$path_fix` when `sizeof($parts) == 1`