D3587: pathencode: fix importing hashlib on Python 3

[Yuya Nishihara]

Queued, thanks.

>  		if (name == NULL)
>  			return -1;
>  
> -		hashlib = PyImport_Import(name);
> +		hashlib = PyImport_ImportModule("hashlib");
>  		Py_DECREF(name);

Nit: `name` is no longer used.