Remove unused cleanup return value

[radarhere]

The return values from C's cleanup() methods

Pillow/src/decode.c

Lines 143 to 150 in d01e2fe

	_decode_cleanup(ImagingDecoderObject *decoder, PyObject *args) {
	int status = 0;
	if (decoder->cleanup) {
	status = decoder->cleanup(&decoder->state);
	}
	return Py_BuildValue("i", status);

Pillow/src/encode.c

Lines 110 to 117 in d01e2fe

	_encode_cleanup(ImagingEncoderObject *encoder, PyObject *args) {
	int status = 0;
	if (encoder->cleanup) {
	status = encoder->cleanup(&encoder->state);
	}
	return Py_BuildValue("i", status);

aren't used in Python.

Pillow/src/PIL/ImageFile.py

Line 423 in d01e2fe

decoder.cleanup()

Pillow/src/PIL/ImageFile.py

Line 702 in d01e2fe

encoder.cleanup()

[akx]

LGTM. Just a small note about zlib, but it's fine (it's been unchecked forever anyway).

[akx]

Looking at the docs, inflateEnd is fallible, but the conditions in which it would fail seem rare enough that it's not worth it to check here:

On error, inflateEnd() shall return Z_STREAM_ERROR. The following conditions shall be treated as an error:

• The state in stream is inconsistent.
• stream is NULL.
• The zfree function pointer is NULL.

So this is fine 👍